Executive Office for United States Attorneys Telecommunications & Technology Developement Video Telecommunications Report #2 prepared by Harvey Press Jerry Lambert August 28, 1995 Video Telecommunications Table of Contents 1 - Introduction 2 - Videoconference Systems Tests - Comparison Charts 3 - Videoconference Systems Tests - Evaluations 4 - Corrections and Updates to Report #1 (EOUSA Pilot) 5 - Document Cameras Tests & Evaluations 6 - Multipoint Tests - FTS 2000 Modification for EVTS 7 - Accessories, Peripherals, Inverse Multiplexors, and Cables 8 - Summary APPENDIX Glossary Introduction The Telecommunications and Technology Development Staff (TTD) for the Executive Office for United States Attorneys (EOUSA) operates a video teleconferencing (VTC) laboratory. The initial purpose of the laboratory was to determine (1) if VTC technologies would be acceptable to the staff of United States Attorneys Offices (USAO); (2) the extent that different manufacturers' video teleconferencing systems could communicate with each other in a standards based environment; (3) which functional VTC applications would have the greatest potential for use in USAOs; and (4) which system(s) would best meet the needs of the USAOs at the lowest cost. The VTC laboratory was coupled with a pilot program which tested a large number of systems from different manufactures for compatibility and interoperability in the standards mode. Operation of the lab continues as new equipment is introduced to ensure that EOUSA's goal of forward and backward compatibility remains intact. On January 27, 1995, TTD issued a detailed report on standards based VTC systems and video teleconferencing capabilities at low speed (bandwidth) 112 kilobits per second (kbs) to higher speed 384 kbs . The following is a detailed report of six additional VTC systems tested in the EOUSA/TTD laboratory since the initial report was issued. This equipment was tested under the same criteria and specifications as the equipment in the January 27, 1995 report. These include 112kbs to 384kbs operating speeds, H.320 ITU standards based VTC systems, interfaces for Dual V.35/Dual RS-366 and ISDN (Integrated Services Digital Network) BRI (Basic Rate Interface) connections using ISDN and SDS (Switched Data Service) transmission services. Also included in this report are corrections to the January 27, 1995, report as well as updates on industry changes to systems previously reported on. Additionally, auxiliary document cameras were tested for operation, capabilities, and overall ease of use in a novice user environment. Results from a six location multipoint (multi-office) videoconference test and a four location multipoint videoconference test are also included to validate multipoint operation and to evaluate capabilities by the Federal Telecommunications System (FTS) 2000 to perform under the new Enhanced Video Transmission Service contract modification recently awarded to the FTS 2000 Network B carrier, Sprint. Finally, the report will provide insight into areas that experienced operators induced problems in the use of accessories, peripherals, and cables for add-ons and system expansion. Some hints and "what to look for" tips are included as a result of these findings. As with the January 27, 1995 publication, this report would not have been possible without the strong support of EOUSA's senior management. Likewise, the efforts of the manufacturers and vendors in cooperating with our laboratory are to be commended. TTD staff appreciates the industry's continued support in providing the most recent systems and peripherals available for testing and evaluation in the EOUSA/TTD laboratory. CLI Eclipse II (8350) - Compression Labs, Inc, provided one CLI Eclipse II single monitor, H.320 compliant Rollabout Video Teleconferencing system for testing in the VTC lab. The Eclipse II makes a successful move into the economical mid range VTC systems. Unlike the earlier CLI rollabout and room systems based upon the Rembrandt and Radiance series codecs, the Eclipse II utilizes a PC based codec. The original entry system of the Eclipse series, the Eclipse I, provided QCIF video and 112/128kbs speeds only. The Eclipse II adds FCIF video, multiple audio algorithms, 336kbs and 384kbs operating speed capabilities which makes the product more attractive to a wider market. Other than the exclusion of the CLI Proprietary Video Algorithm, the Eclipse II's pc based codec has been designed to provide most of the features previously found in the Rembrandt and Radiance codecs. The move to a pc based codec and the CLI application of the H.320 standards places CLI into a very competitive position economically. As tested in the lab, the Eclipse II was configured with a single, 27-inch monitor, both V.35/RS-366 and BRI ISDN interfaces, a VCR, and a CLI SuperCam Document camera. (See specifications in Appendix for details.) The Eclipse II is controlled by a well designed handheld infrared remote control, much like a TV remote control. CLI has successfully produced one of the best remote control units in the industry. The remote is combined with on-screen menus which are simple and easy to follow for selecting the desired function. Unlike the previous CLI systems, the Eclipse II supports inband remote camera control between like systems in a standards based environment. The remote control's only noticeable deficiency as tested is in responsiveness. On several occasions, the remote control buttons had to be double pressed because the system didn't react. It is assumed that the system may not buffer commands from the remote. Thus one must allow the command being executed to completely finish before pressing the next button. The remote control operation did not adversely affect a video call at any time. The Eclipse II was tested with VTC systems reported on earlier as well as the systems included in this report. The Eclipse II handled motion well in the 384kbs and 336kbs operating speeds, and produced one of the highest quality video pictures in this test group. The picture was sharp and clear with good color. In the 112kbs operating mode, the Eclipse II was equivalent in overall quality to all the systems tested in the 112kbs and 128kbs range. Not withstanding, motion was poor and the screen showed 1/2" blocks (or pixeling) with any movement. Lip synchronization was superior at all operating speeds. Audio algorithms have proven to be crucial to successful completion of video teleconference calls. The Eclipse II allows the user to let the system "automatically" negotiate the audio or the user can manually select the desired audio algorithm. This is important when connecting to other VTC systems running H.320 standards. Audio quality was good in all the operating modes. Another important feature of the Eclipse II is its ability to view the current call status. Call status is very useful when troubleshooting and/or assisting the distant end while troubleshooting video call problems. The only deficiency noted is that CLI could have taken the call status one step farther to show both "transmit" operation and "receive" operation. Many times in past tests, although systems have negotiated the audio automatically; the two systems may not complete the video call with the same algorithm. This can affect the "overall" quality of the video call. If this information is known, the video call could be disconnected and reestablished with the proper audio algorithm. Pros: - High quality video picture, sharp, clear, good color saturation - Excellent handheld remote control and on-screen menus user friendly - Audio algorithms automatic negotiation or manually selectable - On-line video call status - Rollabout VTC cart is sturdy, easy to roll, self enclosed, etc. - System easy to use Cons: - 112kbs video calls have poor motion quality, "grainy" - Slow response of System to Remote Control Summary The CLI Eclipse II Rollabout/Room Video Teleconferencing System incorporates most of the required features for a high quality, standards based, VTC including FCIF video, multiple audio algorithms and the capability for 336kbs, and 384kbs operating speeds (bandwidth). The Eclipse II is priced competitively with other H.320 384kbs systems on the market and tested in the lab. The audio algorithms and remote control unit with its user friendly on-screen menus was a huge improvement over previously tested CLI products, and is the best handheld remote tested so far. The unit provides excellent video quality at the 336kbs and 384kbs operating speeds. The Eclipse II (8350) as tested in the lab is a quality mid level video teleconferencing system. Intel Proshare Room (H.320) - The Intel Proshare Room (H.320) videoconference desktop system was tested in the lab under a beta test site agreement with Intel. Since the Intel's original product, the Proshare "Indeo" was not H.320 compliant, that Intel product was not evaluated earlier. Having concluded beta testing, the Intel Proshare Room Video is now on the market. With no additional cost, the Room Video software is included with the Intel Proshare purchase. Intel has been successful in making their low cost desktop Proshare product capable of communicating with other standards based desktop systems and to Rollabout and Room systems running within the H.320 standards. The Intel Proshare is by far the lowest cost VTC system available on the market today. Intel Proshare is limited however in network capabilities. The Proshare can only operate using BRI ISDN circuits. The Proshare Video is QCIF and the only Audio supported is G.711. As demonstrated and tested, the Intel was able to communicate successfully with all VTC systems tested in the lab capable of BRI ISDN (128kbs max). The Intel Proshare is a desktop system making use of two pc boards for CODEC and Audio, an combination ear piece/microphone for audio, and a monitor mounted fixed camera. As mentioned above, the Proshare Video is QCIF and is only capable of a small video window of 320 x 480 max. No external Video outputs are available, but the VGA monitor of the pc can be connected to an VGA to NTSC SCAN converter and output to an auxiliary monitor or screen. The audio inputs and outputs can be replaced by external microphones and speaker systems. The audio quality is G.711 and is excellent. No audio problems were encountered when connecting to other systems. Of the desktop systems tested, Intel Proshare requires a higher level of minimum requirements for the CPU of the pc due to the dependency on the pc's processor for Intel's video operation. Intel's specifications call for a minimum 486 pc with 8 megabytes of RAM. Testing was performed with a 486DX2/66Mhz with 16 megabytes of RAM yet the system was unable to provide better video motion and quality than similarly tested desktop pc video systems. Intel recommends a Pentium and/or an overdrive processor to make the Proshare optimal under today's pc systems. Video motion was always "jerky" and slow. Pros: - Lowest cost VTC available that works - Good audio - Intel "Blue" ISDN provisioning known by Bell Companies - Ease of Use Cons: - CPU operation intensive - Poor Motion, Jerky and Slow - QCIF Video Quality only - G.711 Audio only - 128kbs operating speed max - Can only be used with BRI ISDN (not available everywhere) Summary The Intel Proshare Room (H.320) Desktop Videoconferencing System is a good low cost videoconference alternative. For low budgets and/or experimentation in videoconferencing using ISDN, the Intel Proshare provides capabilities to communicate with all other H.320 standards based systems whether desktop, rollabout, or room without a major monetary investment. QCIF video and G.711 audio provide marginally acceptable performance operation at best. VTEL 127S - Two VTEL 127S Rollabout Videoconference Systems were supplied by the maufacturer for evaluation in the VTC lab. The following report is based on mainly BRI ISDN video calls and some Switched 56 at 384kbs on "answer only" due to the RS-366 board not being provided. (Note: VTEL is providing another unit properly configured for re-evaluation under Switched 56 service.) Like the CLI Eclipse II, the VTEL 127S is a PC based codec rollabout single monitor system. The VTEL 127S VTC system utilizes Windows 3.1, VTEL SMAX software, and Intel Proshare software. The VTEL 127S is Windows based. The software on the VTEL allows user intervention on diagnostics, setup, and dialing control. The 127S software allows manipulation of the Cannon single chip NTSC camera, including pan, tilt, and zoom with the mouse. Intel Proshare is integrated to provide an address book, speed dial list, and application sharing and collaboration. The VTEL 127S connected with all systems previously tested in the lab as well as the systems in this report. The VTEL had excellent video quality, but poor motion handling. The VTEL allows for manual manipulation of the motion to the sacrifice of clarity. Favoring clarity decreased motion, and favoring motion decreased clarity. (Note: VTEL mentioned they were aware of this and are working on the resolution.) Lipsync was always poor and believed to be a direct reflection of the motion handling problem. The VTEL 127S also provides manual manipulation of the audio algorithms. The video has FCIF and QCIF. The 127S provides the highest level of on-line statistics of any system tested in the lab to date. All levels of audio, video, codec, frames, etc. can be viewed while the video call is active. The video screen, icon arrangement, menus, and PIP can be setup and saved as a unique configuration for individuals or groups as needed. This creative ability gives personalization to a videoconference even on a shared system. Pros: - Unique windows setup and configuration - Quick response camera control - Manipulation of Audio Algorithms - Multiple On-line video call statistics - Camera control on pan,tilt, and zoom unique Cons: - Poor motion handling - Lipsync poor - Windows, Mouse controlled Summary The new VTEL 127S Rollabout VTC system is a PC based rollabout videoconference system using Windows 3.1 but not classified as a desktop. The 127S provides the most abundant on-line video call status tested to date, and it allows for manual manipulation of the standards audio algorithms. Though capable of operating at 384kbs, motion control is not handled well and lipsync is off. The ability to change the setup and windows configuration for individuals sharing the same system is unique to the VTEL 127S and can be beneficial to the user. BRI ISDN and Switched 56 were tested, but many other interfaces are supported by the 127S. Overall, the VTEL 127S showed uniqueness and functionality. Once VTEL corrects the motion handling and lip synch deficiencies, it should be one of the top level of standards based systems. PictureTel VENUE 2000 - PictureTel provided a Venue 2000 Roll about VTC System for testing in the VTC lab. The PictureTel VENUE 2000 Single Monitor, PC based rollabout Videoconferencing system is the latest line of PictureTel products to be developed. The VENUE 2000 tested in the lab was configured for a single BRI ISDN line and Dual V.35/RS-366 for Switched 56 services. The VENUE 2000 was also tested with a 3-BRI ISDN Inverse Multiplexor (IMUX) card made by Promptus Communications for PictureTel. The PictureTel VENUE 2000 combines the operation and economics of the desktop PCS-100 with the functionality and appearance of the 4000EX rollabout room system. The VENUE 2000 is pc based, utilizing the same boards found in the PCS-100. Control of the system is from an infrared remote control using menus displayed on a 27-inch Monitor on a cart versus a PC Monitor. The graphical screens provide better clarity than the 4000EX. Also, the VENUE 2000 was configured to provide more "telephone like" sounds on call connects, incoming calls, on-screen statuses, and instructions. As a rollabout, ease of use has improved over the 4000EX. The system responds with "sound" on dialing, answering, errors, busys, etc. The VENUE 2000 signals with an on-screen menu showing the error. The video quality has improved with the VENUE 2000. The picture is sharp, clear, and brilliant. The VENUE 2000 comes with a new camera. This camera has a faster response time than the previous PictureTel unit cameras. It is smoother during operation and movement between PictureTel systems utilizing far end camera controls. The VENUE 2000 can control the PictureTel 4000EX as well as another VENUE 2000 remotely. The audio quality was good and utilized the internal TV speakers. The microphone was a small, unidirectional mic and had to be positioned close to the user when speaking for the remote end to hear clearly. The new Infrared Control unit is responsive, but more difficult to use than the "wired" unit found on other PictureTel VTC systems. The number of keys has increased because "far end" camera control is provided separately on the top half of the unit. Keys now have "pictures" on them as well, but they are so small they hardly make an impact. Likewise, the word descriptions have decreased in size impacting on the ease of use. The old "window" key was replaced with the popular "pip" (picture in picture) key. Remote camera control has problems on response, either it doesn't move with the touch, or it keeps moving beyond the desired location. On the network side, the Dual V.35/RS-366 works identically to the PCS-100. The system performed 112kbs, 336kbs, and 384kbs video calls on Switched 56 with out problems. The ISDN BRI connection worked fine for NI1 single point and multipoint AT&T 5ESS and Northern Telecom DMS100. The 3-BRI did not work on the NI1 single point 5ESS. The 3-BRI board is developed for PictureTel by Promptus Communications. Promptus BRI Inverse Multiplexors require the Bellcore Standard, multipoint ISDN (or two different numbers per line). Using the DMS100 ISDN and the AT&T multipoint 5ESS ISDN, successful 384k video calls were made. The key here is the Inverse Multiplexor is capable of performing Bonding which allows Switched 56 to ISDN and vice versa connections. The Promptus IMUX is providing greater capability for the VENUE 2000 as the IMUX is integrated into the system. The 3-BRI board however, cannot be installed in the VENUE 2000 system at the same time the V.35 or RS-449 board is installed. A configuration or network decision has to be made prior installation and use, but the VENUE 2000 is capable of being more versatile with the 3-BRI board and more economical as it is integrated into the system. Pros: - Lower end system which provides excellent video quality - New camera responds fast and provides excellent quality - Control unit is Infrared, no external wires - On screen graphical menus and "telephone like" sounds - Provides good on-line statistics - Can control far end camera on other PictureTel systems Cons: - ISDN interface limited to Bellcore Standard - Control Unit is less user friendly than previous units - Far end camera operation has response problems Summary The PictureTel VENUE 2000 PC based rollabout videoconferencing system maintains a good level of quality currently provided in other PictureTel VTC systems. The VENUE 2000 is a cross between the PCS-100 desktop system and the 4000EX rollabout room system. New features include a new camera, an infrared control unit, and graphical, color menus. The VENUE 2000 is capable of a maximum 384kbs. It provides 3-BRI ISDN, single BRI ISDN, V.35, RS-449, etc. network interfaces. Provided as an economical system, the VENUE 2000 maintains a high video call quality. Tandberg Grand Vision - The Tandberg Grand Vision Single Monitor rollabout video teleconferencing system was provided for evaluation by the VTC lab by RGB, Inc. The Grand Vision is a rollabout system based on the same codec used by the Tandberg Vision introduced and tested during the EOUSA VTC pilot. The Grand Vision operates under both ISDN, V.35 or RS-449 network. Like the Vision, it operates at 112kbs or 128kbs only. The Grand Vision is setup on a rollabout cart, a 27-inch monitor and a self focusing, movable camera. Operation is with a remote control that is one of the most user friendly and responsive remotes tested. Although the CLI Eclipse II remote has more functionality, the Grand Vision remote is more responsive. The on-screen menus are identical to those on the Vision. Since the Grand Vision is designed as a rollabout system rather as a "videophone" as the Vision , it does not have the handset attached. One other significant difference between the two sysatems is that the Grand Vision utilizes the video input to control the autofocus, pan/tilt camera functions. Network response by the Grand Vision on ISDN is still superior to any of the other VTC systems. However, because of the 27-inch screen, video quality at the lower speeds is not as good as the much smaller screen on the Vision. The Tandberg Grand Vision shows the weakness of quality video calls at low speed on large video monitors. Pros: - Ease of use, still easiest to learn and use - Remote Control unit is most responsive used out of all systems tested Cons: - Video Input on codec is lost to camera - Only operates at 112kbs/128kbs - Larger monitor shows that video quality not as good as small monitor Tandberg Vision Summary The Tandberg Grand Vision rollabout videoconferencing system is a larger Vision in stature only. The Grand Vision adds no new features to the Vision codec. Video quality is not as good as the Vision system due to the larger monitor at low bandwidth operation. The remote control and autofocus camera with pan/tilt makes the system more functional. The remote control unit is responsive and easy to use. The biggest drawback is not being able to operate at higher bandwidths. VSI/BT 2300 - The VSI Single Monitor Rollabout Videoconferencing system installed with a British Telecom 2300 Codec was was provided by VSI for evaluation in the VTC lab. The purpose of this testing was to evaluate the BT 2300 Codec and the VSI as a "single" monitor/cabinet system. The VSI software actually works the same as described utilizing the CLI Rembrandt codec with the addition of a PIP (picture in picture). The camera control, after a video call is established, becomes extensive. For example, extra effort is needed to pan or tilt or focus, and then return to the call in progress. All other functions of the VSI are identical to those previously reported. The BT 2300 full feature Codec was installed with the VSI system. The BT 2300 Codec gives very good video quality on video calls, FCIF. motion handling was excellent in the 384kbs operation. The system is designed to use 7khz (G.722) bandwidth for audio defaulting to G.711 on negotiation. A G.728 audio board is available for the system as well, however it was not installed or tested in this lab as of this report. The BT 2300 Codec can dial RS-366, X.21, has interfaces for RS-449, V.35, Dual V.35, and can operate from 56kbs/64kbs to T1/E1 speeds. Graphics capabilities exist, however they were not tested in this lab. The BT 2300 is also one of the few codecs that has very little powerup and negotiation time, a matter of seconds as opposed to some of the other systems. Pros: - Top quality video, sharp and clear, excellent color saturation - Excellent motion handling - Single monitor solution is step forward for VSI Cons: - Codec as unit alone is higher in price than many complete VTC systems tested - No on-screen diagnostics - No manual manipulation of audio algorithms - Maintenance is specialized and needs technical support for simplest of problems - VSI camera control once call is up takes too many steps to complete - VSI still provides no manipulation by the user of the speed dial list Summary The VSI/BT 2300 single monitor rollabout video teleconferencing system provided excellent video quality and motion handling capability. The British Telecom Codec connected successfully to other standards based systems. The BT 2300 operates up to T1/E1 speeds. The lack of user mediated functionality for maintenance and dialing list capabilities along with a user perception of overall lack friendliness related to camera control, detracts from the high level of video and audio quality of the system. Finally, the VSI single monitor solution with the BT 2300 Codec shows British Telecom does perform in the standards mode and can communicate with other VTC systems. Tests and Evaluations - The EOUSA/TTD video telecommuncations laboratory successfully tested six additional VTC systems operating in ITU H.320 standards and at 112kbs to 384kbs operating speeds. The CLI Eclipse II, PictureTel VENUE 2000, and the VTEL 127S systems represent the corresponding manufacturers mid-range videoconferencing solution and each was introduced this year. These three systems are PC-based, H.320 standards only (no proprietary algorithms), operate between 112kbs and 384kbs speeds, and meet economically between their respective low end products and the high end systems. Video quality and sharpness of picture was excellent in all three systems. The VTEL 127S system had some problems with motion and lip synchronization. VSI, Inc. introduced their new Single Monitor VTC system. As tested in the lab, a BT 2300 codec was used with the VSI system. The BT (British Telecom) codec is the only system in this report capable of T1 speeds. The BT 2300 produced high quality video and motion handling. See Table 1 for comparisons of interoperability.The The Tandberg Grand Vision was introduced in early 1995 as a rollabout version of the Vision and fills a gap at the low end of the price spectrum with a product with operational features nearly identical to the Tandberg Vision. Intel H.320 Room Video software became available late Spring, 1995. Intel was successful in making the desktop product interoperable with all other H.320 compliant VTC systems, however video quality was not increased operating in QCIF only. Table 1 - Matrix showing rating (1-Excellent 2-Good 3-Acceptable) of system to system testing. "NP" Means tests Not Performed From/To CLI Intel VTEL PictureTel Tandberg VSI/BT 2300 Eclipse II Proshare 127S VENUE 2000 Grand Vision CLI Eclipse II NP 3 2 1 3 1 Intel H.320 Proshare 3 3 3 3 3 3 VTEL 127S 2 3 2 2 3 2 PictureTel VENUE 2000 1 3 2 NP 3 1 Tandberg GrandVision 3 3 3 3 NP 3 VSI/ BT 2300 2 3 2 1 3 NP The aforementioned systems were also tested with many of the VTC systems from the original Pilot including the PictureTel 4000EX, the CLI Radiance, the VSI/CLI Rembrandt, the GPT Focus 500, the AT&T Vistium, the Tandberg Vision, the Fujitsu VS700SP, the Sony Trinicom 2000 and the PictureTel PCS 100. All tests were conducted to confirm video call connection capability and interoperability. See Table 2 below. Table 2 - Matrix showing rating (1-Excellent 2-Good 3-Acceptable) of current system to other VTC systems. "NP" Means tests Not Performed From/To 4000 Vision PCS100 Sony Radiance VSI/CLI GPT Fujitsu AT&T CLI Eclipse II 1 2 2 2 1 1 2 2 3 Intel H.320 Proshare 3 3 3 3 NP 3 NP NP 3 VTEL 127S 1 2 2 2 NP NP 2 2 3 PictureTel VENUE 2000 1 2 1 1 NP 2 2 NP 2 Tandberg Grand Vision 3 1 3 3 3 3 NP NP 3 VSI/ BT 2300 1 2 2 2 NP 2 1 2 NP Again, the audio algorithms proved the most important single feature directly affecting video teleconference calls at all speeds. The standards audio algorithms, G.711, G.722, and G.728 affected all the VTC systems in connecting successfully. All systems with the exception of the Intel H.320 have the ability to perform "automatic" negotiations on audio. (The Intel H.320 system had excellent audio quality, however G.711 is the only algorithm available at this time.) Once again, the systems tested had to be placed in a proper audio mode for a guaranteed successful video call. All systems could successfully connect once a proper adjustment was made. See Table 3 below: G.711 operates at 300 - 3.4khz over 64kbs of bandwidth (First and default audio standard) G.722 operates at 50 - 7.0khz over 48 or 56kbs of bandwidth (Operates best for high speed video calls) G.728 operates at 300 - 3.4khz over 16kbs of bandwidth (Newest standard, helps with low speed video calls) Table 3 - Video Teleconferencing Systems' Standards Audio Modes VTC System 112k/128k 384k Automatic CLI Eclipse II G.711, G.722, G.278 G.711, G.722, G.728 yes Intel H.320 Proshare G.711 only DNA no VTEL 127S G.711, G.722, G.728 G.711, G.722, G.728 yes PictureTel VENUE 2000 G.711, G.722, G.728 G.711, G.722, G.728 yes Tandberg Grand Vision G.711, G.722, G.728 G.711, G.722, G.728 yes VSI/BT 2300 G.711, G.722 G.711, G.722 yes Both ISDN and SDS transmission services were again used as the transport mediums for the lab. ISDN operated at 112k, 128k, 336k, and 384kbs speeds. The PictureTel VENUE 2000 was the only system capable of 336k and 384kbs speeds straight from the box. The previous Pilot used ISDN provided under AT&T NI1 standards from Bell Atlantic in a "single point" arrangement. The ISDN testing performed in the lab included AT&T NI1 for single point as well as multipoint arrangements. Northern Telecom DMS100 service was also utilized in a multipoint arrangement. SDS (or Switched 56) Services were provided by Sprint via the FTS 2000 contract with an Ascend Multiband Plus Inverse Multiplexor. SDS was ordered with seven channels to provide operating speeds between 112k and 384k (the seventh channel was used for aggregated 384k). Once again, the inconsistancies associated with ISDN line provisioning proved time consuming and difficult to correct the first time installed. See Table 4 below for list of systems operating on ISDN or SDS. Table 4 - Video Teleconferencing Systems' Operating Transmission Service and Speeds Pilot Report "corrections" and "updates" VTC Systems ISDN Service SDS (Switched56) Service CLI Eclipse II yes yes, 112k-384k Intel H.320 Proshare yes, 128k no VTEL 127S yes, 128k yes, 112k-384k PictureTel VENUE 2000 yes, 128k-384k yes, 112k-384k Tandberg Grand Vision yes, 128k yes, 112k VSI/BT 2300 no yes, 112k-384k AT&T Vistium - 336kbs & 384kbs speeds with external IMUX) (discontinued) - Switched 56/64kbs now available - "Grey Bar" image corrected on remote system CLI Radiance - LCD control panel updated to allow faster connect time - 40 seconds now CLI Rembrandt - Option package III was tested in Pilot Fujitsu VS700SP - X.21 interface works well in "dialup" mode - Single BRI interface board now working - No Dual V.35/RS-366 interface projected, use X.21 interface instead GPT Focus 500 - Codec now configured for Dual Port V.35/RS-366 access for 112kbs speed and single port 384kbs access without needing to change cables on IMUX (at present not available) PictureTel PCS 100 - New software version 1.5, includes far end camera control on other PictureTel Room systems, and full screen video image - Version 1.5 software release also corrects the inability to operate at either single line ISDN (2B) and V.35 without changing setup/configuration PictureTel PCS 100/Promptus Oasis 200B - A PictureTel PCS 100 was connected to a Promptus Oasis 200B inverse multiplexer to test 3 BRI ISDN lines at 384kbs. The system produced results equal to those using the FTS 2000 switched 56 services reported in the January 27, 1995 report. PictureTel 4000EX - New "Power mic" microphone successfully filters out background noise - G.728 audio option now standard on 4000 Sony Trinicom 2000 - 336kbs speed operation now available in "black box" configuration - Remote control infrared spectrum increased - 3-BRI built-in IMUX not Bonding compliant Tandberg Vision - 384kbs speed capability under development, expected in fall 95' - upgraded Codec for dual number dialing - screens updated to show call quality VSI - Introduced two new, single monitor cabinet configurations - Introduced integration of PC-based Codec for low speed operation, working on higher speeds as well. New codec lowers overall price of VSI system Document Cameras Tests and Evaluation Tests were performed on six document cameras provided for the EOUSA/TTD Video Laboratory. The document cameras tested were: - Elmo EV-308 - Elmo EV-400 - Canon RE-650 - Sony VID-100 - DOAR (Elmo EV-368) - CLI SuperCam These cameras were setup side-by-side in a classroom environment for evaluation. The following tests were designed to evaluate the capability of the document cameras in providing clarity of images, capabilities or limits on viewing text and documents, and the ease of use. The following tests were performed: Test 1 - 11" x 8-1/2" page of text viewing (landscape) Test 2 - 8-1/2" x 11" page of text viewing (portrait) Test 3 - Transparency capability & clarity Test 4 - Film Negative capability & clarity Test 5 - Slide viewing capability & clarity Test 6 - Drawings (or graphics) images clarity, color Test 7 - 3-D (small object) capability & clarity Test 8 - 3-D (building model) capability & clarity, detail Two other tests originally scheduled to be performed were not completed. These tests were for signature and fingerprint detail & clarity. As testing progressed, it was determined that the cameras compared very close to each other and presented nearly identical clarity, detail, and results. Each of the document cameras, with the exception of the CLI Supercam, has the capability to change the current lens with another more or less powerful lens if required. Though the above mentioned two tests were not performed in the side-by-side testing, each camera was used to view a signature and fingerprint. As a casual observation, the 8x power lens showed great quality and detail. The Canon RE-650 document camera had a 12x power lens which provided even greater closeup detail. Most systems come with the 8x power lens as a standard. Text viewing or text reading capability on screen were the most crucial tests performed. Since U.S. Attorneys dealing primarily in normal printed and written text, it was important to see each camera operate with an 8-1/2" x 11" page of text. The results of these tests were identical for all cameras. Typical text font is 10pt or 12pt. Handwritten text is similar in size. The tests indicate 14pt text at the very minimum, preferably 18pt is the optimal way to display an 8-1/2" x 11" page of text legibly. The expectation was to view an entire page of text legibly, in a manner similar to what is seen on an overhead projector. None of the cameras produced equivalent results. Therefore, when viewing normal text, the page has to be positioned and the document camera has to be zoomed in for it to be readable. Use of a stronger auxillary lens would increase the size of the printed material and make it more readable but it also would decrease the area of the displayed material in the same manner as enlarging portions of the document through use of the zoom controls on the cameras. Once again, 14pt to 18pt text on a page should be used in order to be legible without manipulation of the page. Generally, all of the document cameras were identical when it came to text viewing, however when it came to colors, the cameras varied. The camera in the Elmo EV-400 excelled in color detail. All cameras showed the colors however in the wide-angle views (or the full page views) all except the Elmo EV-400 showed red to be dark or black. The Sony VID-100 did pick up the red, however it had problems with green as did the rest of the cameras. The problems were associated with a wide-angle view or full page, colored text, and colored fine lines. Color images or the graphic images in the transparency and graphic tests appeared to show the colors effectively with all the cameras. Differences were noted when performing closeup views. The 12x lens on the Canon RE-650 provided the sharpest image views, but the Elmo EV-400, the Sony VID-100, and the DOAR Visual Presenter (Elmo EV-368) were more brilliant in colors and produced near the same sharpness. The CLI SuperCam was good with colors. The Elmo EV-308 didn't perform as well in this area of testing. Vendors and Manufacturers point out that versatility of the document cameras is a big selling point. The document camera is routinely presented as a device that can view text, graphic images, objects, transparencies, film negatives, pictures, slides, etc. With a document camera, a user may not need additional types of periphial equipment. The versatility of the document camera was proven in testing, however experience is the key in using the document camera effectively. Also, not all document cameras can perform all the previous mentioned functions. The transparency test, the film negative test, and the slide test require a backlighted source on the stand in order to view the image. The Elmo EV-400 and the DOAR Visual Presenter (Elmo EV-368) were the only document cameras with a light source large enough to cover an entire 11" x 8-1/2" sheet. The Sony VID-100 was slightly smaller but could effectively get an entire image into the light. The Canon RE-650 as tested and as purchased does not have a backlighted source. Canon sells separately a "light box" which is used to provide lighting for transparencies or other materials. The Elmo EV-308 document camera only has a 6"x6" light source. This was found in testing to be very ineffective. The CLI SuperCam does not come with that capability, but like the Canon RE-650, a light box can be purchased. Next, the 3-D object tests were performed. The small object test is simple because the object was set on the document camera stand under the normal position of the stand's camera. The small object 3-D capability is very effective and tested with high quality results. On the 3-D building model test, the document stand was no longer capable of holding the model. This is where expertise becomes important, utilizing the ability to turn the camera to view in front or on the wall, a larger object is capable of being viewed. During this test, the model was set on a table in front of the document camera, then the camera is rotated to view the model in front. This resolved the size issue and effectively projected the model and detail. Again, the 3-D view was highly effective. Detail and clarity was exceptional in most of the cameras. The Sony VID-100 excelled in this test. The unique camera "torut" allowed for movement of the camera in all directions and allowed for the camera to pan from one side to another as well as up and down. All the other cameras could only move up and down. The Canon RE-650 showed quality detail, however it could not show the model view without the room lights turned on and the camera had to be held in position for the view as it could not become stationary in the necessary position. The Canon RE-650 lost the light necessary once it was directed away from the stand, even with the room lights up. The Canon was the only document camera tested where this happened. The other cameras were able to function on the stand and view the model with or without the room lights. The 12x power lens again showed greater detail on closeup views. Finally, overall use was evaluated. As primarily novice users, we found the Sony VID-100 gave the greatest overall ease of use capability with the Elmo EV-400 coming in very close while providing better camera quality in all the tests. The DOAR Visual Presenter came next as it does not have autofocus capability. After that, the ranking is Canon RE-650, the CLI SuperCam, and the Elmo EV-308. The Canon document camera lost ground in versatility as its stand or camera arm was rigid and not flexible. The eight tests performed showed the more flexible or versatile the document camera, the more it excelled in ease of use. The CLI SuperCam was extremely flexible, however like the Elmo EV-308, the controls are on top of the camera. The controls being on the camera instead of in front make it hard to operate the document camera during a presentation. Overall, the document cameras could perform in the tests, the cameras alone weren't as important a factor in operation as the entire package of the document camera and stand proved to be. The fact normal text can not be presented any differently was a major concern as a result of testing. Please see the document camera table below. Multipoint Tests - FTS 2000 Modification for EVTS In May, the FTS 2000 contract was modified allowing Sprint to provide Enhanced Video Transmission Service (EVTS). EVTS service consists of the Sprint Video Group's Meeting Channel in Atlanta, Georgia. This provides interconnection for Interactive Multipoint Videoconferencing. The service provides multipoint capabilities, codec conversion, rate matching, gateway service to dedicated video services both FTS 2000 and commercial, access to Network A (AT&T), scheduling, and technical support. Switched 56 (or dialup) services are relatively new at the Sprint Video Group (SVG) and testing was performed to verify the service capability and the effectiveness of multipoint videoconferencing. Switching from one location to another for multipoint videoconferencing is chair controlled and/or voice activated. The technology does not allow for multiple sites to be presented at the same time on the same screen. Chair controlled or voice activated switching allows multiple sites to participate in the same videoconference with the current speaking site viewed by all participants. The testing completed was provided in two multipoint videoconferences. The results of the two multipoint videoconferences were positive. The first multipoint videoconference consisted of six sites participating and the second multipoint videoconference was performed with four sites attending. See Table 1 below. Table 1 - Multipoint Videoconference Tests Site Multipoint Test 1- 384kbs Multipoint Test 2 - 384kbs Washington DC EOUSA/TTD Lab X Brooklyn, NY Cleveland, OH X Kansas City, MO X X Houston, TX X X San Diego, CA X El Centro, CA Beaumont, TX X Washington DC EOUSA OLE Classroom Atlanta, GA Meeting Channel X X The two Multipoint tests were completed successfully. Connections came up quickly and the voice activated videoconference worked well. Instead of seeing all sites in the conference call up at the same time on the screen, the voice activated switching showed the current speaker or the last spoken site. The switching was not a problem. All sites could hear, see, and interactively participate in the meetings. The results proved EVTS at first glance to be effective. Further use of the Meeting Channel and EVTS from the FTS 2000 contract will determine the overall success and effectiveness of the service. Accessories, Peripherals, Inverse Multiplexors and Cables In the course of testing VTC systems, it became apparent that performing audio and video communications between two or more sites was not the exclusive benefit of video teleconferencing. Accessories and peripherals have added to the functionality by providing more capabilities than originally anticipated. However, as learned at the very first testing session, cables have caused grief and problems. Accessories used and evaluated in the EOUSA/TTD video lab range from VGA-to-NTSC TV Scan converters for making PC video available on television screens and monitors to electronic drawing tablets for highlighting and editing graphic images. See the following: - Mediator VGA-to-NTSC TV converters (used by all PCs) - Sony Drawing Tablet (used by Sony Trinicom 2000) - Sony Scanner (used by Sony Trinicom 2000) - PictureTel PCS 100 camera stand (allows camera to view documents) - PictureTel Drawing Tablet (used by PictureTel Room systems) - PictureTel Powermic (microphone used by PictureTel Room systems) - CLI SuperCam (document camera for CLI Eclipse room systems) Peripherals evaluated include the Document Cameras, Color Video Printers, auxiliary cameras, Scanners, TV monitors, Electronic White Boards, etc. These are devices that can be used by any of the VTC systems or audio/visual systems. See the following: - All document cameras tested - Sony Color Video Printer - Sony document scanner - Softboard Electronic Whiteboard (needs a PC with Windows 3.1) - All video/stereo capable TV monitors and tuners - NTSC & RGB type cameras (note: RGB is not on all systems) - Text/Graphic Printers (note: special connections apply, not all systems) Inverse Multiplexors (IMUX) are devices that allow multiple channels (or telephone lines) to be multiplexed for the proper operating speed and connection service. The EOUSA/TTD lab uses Ascend Multiband IMUXs provided by Sprint, FTS 2000 as part of the transmission service. Promptus Communications also provides a similar IMUX which was tested in the lab using Switched 56 transmission services, the Promptus OASIS T IMUX. In operation, the OASIS T performed much like the Ascend. The only differences were in the dialing profile directory. Ascend requires a #00x preceding the telephone number to be dialed where the Promptus requires a #x* preceding the number. Both IMUXs aggregate the 7th channel to allow for the 384kbs speed capability between like IMUXs. In connecting from the Ascend to the Promptus and visa versa, a "Bonding Mode" had to be selected. Each IMUX in their native configuration is proprietary. In the bonding mode, both IMUXs operated on a channel by channel basis with 336kbs speed being the maximum allowed under the lab's configuration of 7 channels. The 384kbs cannot be obtained between the different IMUXs in the 7 channel configuration or bonding mode. The interfaces on the two IMUXs are completely different. The Ascend uses a DB-44 proprietary pin configuration requiring a "Y" cable for RS-366/V.35 interface. The Promptus OASIS T requires two cables per port with again special cables. See the following configurations tested in the lab: Ascend Multiband Plus: - RS-366 dialing - 112kbs Dual port profile (two cables) - 336kbs single port profile in bonding mode - 384kbs single port profile in AIM, Delta mode Promptus OASIS T: - RS-366 dialing - 112kbs Dual port profile (four cables) - 336kbs single port profile in bonding mode - 384kbs single port profile using "7th channel" selection Cables have presented the greatest problem in connecting video telecommunications systems, accessories, and peripherals. Every manufacturer uses different cable configurations for various forms of Network Interfaces. The EOUSA/TTD lab focused on Dual V.35/RS-366 interfaces with an Ascend Multiband Plus IMUX. Most VTC vendors recommended and/or brought their own cables for connection to the Ascend IMUX. On the ISDN side, all cables are identical for all systems and therefore standard. The ISDN interfaces use a single cable type with a RJ-45 connector. Audio and Video cables are more standard, however VTC manufacturers often use proprietary interfaces for cameras, microphones, and other audio/video inputs and outputs. The PC based systems provide only one type of interface for VGA video, standard parallel ports, and serial COMM ports. However, manufacturers integrate audio/video boards into PCs and these may have proprietary interfaces. Watch out for both the network interfaces and the audio/video interfaces on the systems. The following is a list of the typical (or standard) interfaces: Network: V.35, RS-449, X.21, DB-25, RS-366, RJ-45, and T1/PRI(RJ-45) Audio/Video: BNC, RCA(composite), S-video, F-type, and RGB PCs: 15-pin VGA, 25-pin Parallel, 9-pin, 15-pin & 25-pin serial The primary focus in the evaluation of peripheral equipment has been to extend to improve upon the original operation of the VTC system. Based on requirements and needed options, a VTC system can be selected based also on the capabilities of accessories and peripherals for the enhancement of videoconferencing services. Most systems are multifunctional, but some require proprietary components while others allow for standard or off the shelf components. Summary The EOUSA/TTD video teleconferencing laboratory continues to operate beyond the initial pilot in order to provide further testing and evaluation of VTC systems and to evaluate new emerging video technologies. In this report, EOUSA/TTD tested and evaluated six VTC systems not available in 1994. The technology of VTC is changing more rapidly than companion technologies. At this writing, new systems are scheduled for availability later this year, other new systems are being developed which add to or go beyond this years systems, and new telecommunications services are helping pave a path for these systems to operate. The six VTC systems tested were all ITU H.320 standards based operating from 112kbs to 384kbs speeds. Of the systems tested this period only the BT 2300 was capable of T1 speeds. The Intel H.320 Proshare allows Intel's VTC system to communicate with all other H.320 systems where prior to this year, Intel was completely proprietary. The CLI Eclipse II, the PictureTel VENUE 2000, and the VTEL 127S are all PC based, H.320 standards only, rollabout cart systems operating from 112kbs to 384kbs speeds. They all provide qualities inherent in their respective "franchise" top of the line systems, but bring the cost down to the high end of the desktop category for video communications. The VSI system hasn't changed at this point in overall operation, however a pc based single monitor system allows for greater flexibility over the prior dual monitor room system. The VSI is still capable of using any manufacturers' codec and has integrated a pc based codec into the system for low end requirements keeping overall cost down. Overall, the above systems have successfully operated between each other as well as systems tested in the previous EOUSA Pilot. The previous EOUSA Pilot tested and evaluated nine different VTC systems. Since that pilot, all nine systems have undergone upgrades and changes. Continued use and work with these systems have provided new information related to the Pilot's tests and evaluations as well as helped to drive some changes which have been incorporated by the manufacturers. The Fujitsu VS700SP was not tested for X.21 dialing as stated in the Fujitsu VS700SP specifications in the Pilot, however X.21 dialing from the Fujitsu and works well. Fujitsu still provides no RS-366 dialing capability and this needs to be addressed in either IMUX configuration or future development and support by Fujitsu. The GPT Focus 500 system tested in the Pilot was also upgraded to successfully allow for the RS-366 dialing and dual port capabilities. Continued watch on GPT's codec direction is recommended. (Review section 4 on corrections and updates to those systems.) Document cameras were tested and evaluated in the lab for the ability to compliment the VTC system in a videoconference. The document cameras were tested for ease of use, clarity, versatility, and most importantly, capability to see normal text on 8-1/2"x11" documents. (See section 5 for list of tests performed.) The tests proved invaluable as the ability to read normal text was "unobtainable" on all cameras. The manufacturers and vendors confirm this finding as the technology does not support the capability. There are physical limitations to the cameras and to NTSC. The users wanted a capability similar to using a standard overhead projector. Alternative methods to broadcasting normal text is to either reformat the text for 14pt or higher fonts, or use the zoom capabilities and manipulate the document. The successful tests showed ease of use, clarity, and versatility. Two document cameras excelled above the other cameras, the Elmo EV-400 and the Sony VID-100. A third document camera, the DOAR Visual Presenter (or Elmo EV-368) was a close second, but did not have autofocus capability. The Elmo EV-400 was strong in camera operation and viewing colors, and the Sony VID-100 was the most versatile document camera because the stand and camera moves in any direction. The Sony also had a built-on close up lens whereas the Elmo had to be moved in or out with the camera mount arm. The Canon RE-650 has great camera quality and is the lowest priced, but lacks versatility. Multipoint testing and the new FTS 2000 Modification for EVTS (Enhanced Video Transmission Service) were evaluated. These tests were to confirm EVTS capability, analyze voice activated video switching, and get a general user's perception of multipoint videoconferencing. The two videoconferences were successful, the user perception was favorable, and connections to the Sprint Meeting Channel were made easily. Two problems arose, but they were correctable and not a reflection of EVTS capability. Accessories, peripherals, Inverse Multiplexors, and cables were discussed. Many accessories and peripherals have been evaluated for use with the VTC systems. Accessories and peripherals help make VTC systems and videoconferences more robust and effective. With accessories such as VGA-to-NTSC TV converters, desktop (or pc) VTC systems can be expanded to become room type equivalent systems. Document Cameras enhance videoconferences by allowing better information sharing with text, graphics, and objects. Two inverse multiplexors were tested in the lab, the Ascend Multiband Plus and the Promptus OASIS T. Currently EOUSA/TTD and U.S. Attorneys use the Ascend Multiband IMUX for communications. The Promptus IMUX is similar to the Ascend and both systems can communicate in bonding mode. Cables are important and tend to cause the most problems. Switched 56 network cables are different between IMUXs and different between Codecs. ISDN cabling is standard and always the same. Audio/Video cables have standards, however many manufacturers utilize proprietary interfaces in connecting accessories and peripherals. Be sure of the cable interface before purchasing. Finally, testing and evaluation is essential to learning this new technology and determining strengths and weaknesses in it. The new systems tested in the lab since the Pilot Report of January 27, 1995 show the rapid progression and pace in videoconferencing and video telecommunications in general. These systems reinforce the idea that standards based VTC systems are important and essential to the continued development of video communications. The driving force behind VTC system development and purchases is the ability to achieve interoperability, the ability to perform videoconferences to anyone, anywhere, anytime. Standards based VTC systems and "dialup" video telecommunications are now available which confirm the direction of technology and the industry. GLOSSARY Definition of Terms, abbreviations, and acronyms: ************************************************************************************ ANSI: American National Standards Institute ASCII: American Standard Code for Information Interchange Audio: The voice or sound portion of a teleconference. BRI: Basic Rate Interface Camera: In television, an electronic device using an optical system and a light-sensitive pickup tube or chip to convert visual signals into electrical impulses. CCITT: International Telegraph and Telephone consultative Committee (now ITU-T) CIF: see Full Common Intermediate Format. CODEC: Acronym for COder/DECoder. Video Teleconferencing unit which performs coding/decoding of audio and video, and multiplexing of video, audio, data, and control signals, system control, and end-to-end signaling. Conferencing: Programs and meetings which may be for the purpose of presenting and exchanging information, comparing views, learning, planning, and decision making. Conferences can be held in one location or conducted simultaneously at multiple locations and linked together by telecommunications systems. Data Port: A port used to transfer information between functional units by means of data transmission, according to a protocol. Data rate: In digital data communications, the rate at which data (bits in this case) is transmitted, usually expressed in bits per second. DB-25: A standardized 25-pin connector used in EIA-232 (RS-232) data communications. Desktop or Individual Workstation: An input/output display device that allows an individual to perform some work local or remotely; literally small enough to sit on a desktop. DSU: Data Service Unit EIA-232 (formerly RS-232): A serial interface standard for transmission of unbalanced signals between a variety of computer, media, and multimedia peripherals. EIA-232 uses a 25-pin connector and is rated for 19.2 kbit/s for up to 50 feet. EIA-366 (formerly RS-366): Interface between data terminal equipment and automatic calling equipment for data communications. EIA-449 (formerly RS-449): A serial mechanical interface standard for transmission of balanced and unbalanced signals between a variety of higher-end computer, media, and multimedia peripherals. EIA-449 allows a maximum data rate of 10 Mbit/s and uses a 37- or 9-pin connector. Electric Industries Association: A U.S. commercial standards organization. The acronym EIA precedes a numerical designation, such as EIA-232, which replaces the now obsolete but commonly used RS (Recommended Standard) designation. Encoder: A device that encodes. Encryption: The process of encrypting. Full Common Intermediate Format (FCIF): A video format defined in ITU-T H.261 that is characterized by 352 luminance pels on each of 288 lines, with half as many chrominance pels in each direction. G.711: ITU-T standard, Audio algorithm operating at 300hz - 3.4khz using 64-kbs bandwidth. G.722: ITU-T standard, Audio algorithm operating at 50hz - 7.0khz using 48/56-kbs bandwidth. G.728: ITU-T standard, Audio algorithm operating at 300hz - 3.4khz using 16-kbs bandwidth. H.221: ITU-T standard, Frame Structure for a 64 to 1,920 kbs channel in audiovisual teleservices, March 1993. H.230: ITU-T standard, Frame-Synchronous Control and Indication Signals for audiovisual systems, March 1993. H.233: ITU-T standard, Confidentiality System for audiovisual services, March 1993. H.242: ITU-T standard, System for establishing communications between audiovisual terminals using digital channels up to 2 Mbs, March 1993. H.261: ITU-T standard, Video CODEC for audiovisual services at Px64 kbs, March 1993. H.320: ITU-T standard, Narrowband visual telephone systems and terminal equipment, March 1993. Hz: Hertz IMUX: Inverse Multiplexor Inverse multiplexor: A device used to create a single, higher-speed network data channel by combining, separating, and synchronizing multiple, independent 56- or 64-kbits/s network data channels. Also known as an aggregator. ISDN: Integrated Services Digital Network. Access channels include a basic rate (two 64-kbs "B" channels + one 16-kbs "D" channel) BRI and a primary rate (twenty three 64-kbs "B" channels and one 64-kbs "D" channel) PRI. ITU-T: International Telecommunications Union - Telecommunication Standardization JPEG: Joint Photographic Experts Group kbs: Kilobits per second (also kbit/s) khz: Kilohertz Mbs: Megabits per second Multipoint: A telecommunications system that permits three or more locations to intercommunicate in a conference call. u-law: The PCM coding standard used in Japan and North America for G.711. Network: Network infers the system of cables, microwave links, fiber optics, and switching centers that allow the transmission of data as opposed to the terminal equipment (such as CODECs and I/O devices) connected to the cables. NT1: Network Termination 1 NTSC: National Television Standards Committee Px64: Family of 5 ITU-T Recommendations. These include H.261, H.221, H.242, H.230, and H.320. These standards for the basis for Video Teleconferencing (VTC) interoperability. PCM: Pulse Code Modulation PRI: Primary Rate Interface Quarter Common Intermediate Format (QCIF): A video format defined in ITU-T H.61 that is characterized by 176 luminance pels on each of 144 lines, with half as many chrominance pels in each direction. QCIF has 1/4 as many pels as FCIF. Restricted Channel: A digital communications channel for which each increment of 'P' gives a useful capacity of only 56000 bits per second (56-kbs), instead of 64000 bits per second (64-kbs). This is currently common in North America, and was originally due to a ones density limitation in T1 circuits. Terminal Equipment: A device or devices connected to a network or other communications system used to receive or transmit data. It usually includes some type of I/O device. Unrestricted Channel (clear channel): A digital communications channel, in which for each increment of 'P' all 64000 bits per second (64-kbs) are available for information transfer. ISDN is an example of a network that uses 64-kbs communications channels. Video: That portion of a signal that is related to moving images. Videoconferencing: See Video Teleconferencing. Videophone: A VTC terminal where most of the equipment is integrated into a single desktop unit. Video CODEC: See CODEC. Video Teleconferencing (VTC): Two-way electronic form of communications that permits two or more people in different locations to engage in face-to-face audio and visual communications. meetings, seminars, and conferences are conducted as if all the participants are in the same room.