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Test Report Cisco SX 20

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Cisco SX 20General

Period

March 2013

SW Version

TC 6.0.0

Device Class

The device Cisco SX 20 is a High Definition video conference system with a resolution of up to 1920x1080 (1080p). Due to the fact that image formats starting with CIF (352 x 288) can be used and the adjustment to the available bandwidth of the connection, it is also compatible with older H.323 systems. The device is designed as a group system. For displaying the images of the remote side, up to two monitors or beamers can be connected.

Scope of Delivery

The Cisco SX 20 is offered on the market with two different cameras. There is one version with 4x zoom and one with 12x zoom. Both cameras are Full HD capable (PrecisionHD 1080p). The system is always delivered with codec, camera, microphone, remote control and all the necessary cables. An additional microphone can be purchased optionally.

Bandwidths

The system can be used with bandwidths of up to 6 Mbps for video conferences in the LAN area. The protocols H.323 or SIP can be utilized.

For operation in the ISDN area, the device "Cisco TelePresence ISDN Link" is additionally necessary. Consequently, a maximum of 4 channels (= 512 kpbs) or a PRI port (=1920 kpbs) are possible with BRI.

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Installation

The installation is simple with the help of the documentation that is provided. Availability can be reached quickly.

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Test

Start / Power Consumption

After switching on the power, the system is ready for operation after about 1 minute. During this time, only a light on the device signals the boot routine. No additional feedback is provided on the display.

The typical wattage is about 135 kWh per year.

Operation

The system is mainly controlled via remote control (TRC5), which expands the previous models by context dependent control keys. Depending on the menu item or connection state, different options are displayed at the bottom of the screen when using the remote control, which can be selected with the help of the respective keys (for example, it is possible to switch to Far End Camera Control during an existing connection).

The software corresponds to that of the Cisco Codec C Series. The clear labelling and arrangement of the menu items as well as the intuitive menu navigation guarantee a fast and purposeful navigation of the system. First users can orient themselves quickly due to the clear structures.

Operation via a password-protected web interface is possible as well. Optionally, a touch panel is offered by the manufacturer to control the system.

Audio

Two separate microphones can be connected to the device. Each microphone possesses its own echo canceller. Mainly HDMI is intended for the audio output. Additional line ports are provided for audio-in and audio-out.

The audio quality was very good in all connections. G.722, G.722.1 or AAC-LD were used as codecs.

Video

The resolution 1920 x 1080 (1080p) is only possible with the option Premium Resolution, otherwise a maximum of 1280 x 720 (720p) is offered.

With the Cisco SX 20 the negotiated resolution and frame rate of a connection do not only depend on the bandwidth, but also on the setting of the video mode to "Motion" or "Sharpness". The setting "Motion" as default value optimizes the frame rate, "Sharpness" guarantees the maximum resolution as long as possible for different bandwidths. For instance, with a bandwidth of 6 Mbps, for a maximum setting of "Motion" the connection is established with 720p@60, for "Sharpness" with 1080p@30.

As an extension of the traditional presentation "picture in picture" (PIP), when using only one playback device, the alternative "picture outside picture" (POP) is offered. In the latter case, the self view and the remote side are arranged in such a way on the display that they do not overlap. Consequently, the user can choose between three different layouts to achieve the optimum presentation for the given conditions:

Cisco defines three profiles that can be chosen, because the quality of the image transmission also depends on the room's lighting conditions:

All our tests were carried out in normal mode.

The quality of the transmissions in the video area were always rated very good with one exception. Solely the desktop system Polycom m100 had great difficulties to show the received image with 720p@30, which lead to a massive disturbance of the display. Furthermore, the m100 only sends VGA to the remote side.

H.264 was always negotiated as codec in both directions. In connections with modern devices (e.g. RADVISION XT 5000, Cisco C40) the theoretical maximum values were used. But also for older devices 720p are almost always possible as image format.

H.239

A PC/laptop for the parallel data presentation can be connected via analogous RGB or DVI-I. The device detects the connection automatically. For using H.239, the optional Natural Presenter Package has to be activated.

When the second data channel is in use, the mode POP as well as PIP is offered. Especially for plasma and LCD displays with 16:9 aspect ratio, POP is a good alternative. Overall, five different layouts are offered for H.239:

The transmission in the second video channel is carried out with a maximum resolution of 1920 x 1080 pixels at 15 fps (Cisco EX 90, RADVISION XT 5000). Reception and sending of static content (e.g. slide shows) were in very good quality in most tests. Only in the case of the LifeSize Team 220, a resharpening time of up to 6 seconds was observed, which impacted the usage negatively in parts. With the SONY PCS-XG 80, data presentation was not possible at all.

For the transmission of videos with the help of the data channel in SD or HD resolution, the technical equipment of the remote side plays a very important role. With modern devices, transmissions of high-resolution films are possible in both directions with 720p@30 or 1080p@15. There is no visible difference to a local presentation. In connections to older remote sides, the negotiated image rates of 4-5 fps are just practically applicable for SD films in the data channel, for HD films they are not applicable anymore.

Detailed test results can be found in the compatibility matrix.

Camera Remote Control

Controlling the camera worked in all tests als long as the requirements were met.

Service DFNVideoConference

Collaboration with the MCUs within the service DFNVideoConference worked without restrictions. The audio and video quality was very good. AAC-LD as well as H.264 were used with 720p@30 (sending direction) and 1080p@25 (receiving direction).

Collaboration according to H.239 worked with H.263++ and 720p with very good quality for presentations as well as SD and HD videos.

Gatekeepers

Collaboration with the gatekeepers GNU-GK and CISCO MCM worked faultlessly.

Camera Test and Test Images

Tests of the test images for resolution and colour fidelity show that the PrecisionHD 1080p does not change any colours in the spectrum of the muted natural colours and records the colour values authentically. The visual resolution corresponds to the capabilities of current HD cameras. The image quality is very good. Colour, sharpness and contrast are outstanding and the camera control (pan/tilt/zoom) works fast and silently. The autofocus was convincing as well.

SIP

Calls to the MCU within the service DFNVideoConference are possible via SIP dialling with the syntax "conference ID@mcu.vc.dfn.de". A data transmission in the second channel, with BFCP, is possible.

URI Dialling

Calls through URI dialling according to H.323 Annex O are only possible after registering successfully with one of the gatekeepers. In that case, the syntax "conferenceID@194.95.240.2" is used.

Encryption and Firewall Traversal

Transmission encryption with AES according to H.235 always worked in all connections.
The device supports firewall traversal according to H.460.18 and H.460.19.

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Conclusion

The group system Cisco SX 20 is a powerful video conference system with a very good price performance ratio, which operates at the top of what is technically feasible currently. In connections with modern systems, it convinces in all areas, but conferences with older systems are also possible. In the latter case, only part of the entire system performance is used though.

Documentation

Manufacturer: Cisco
Distributor: MVC

Supported standards H.323, SIP
Audio encoding G.711, G.722, G.722.1, 64 bit MPEG4 AAC-LD
Video compression H.263, H.263+, H.264
Bandwidth Up to 6 Mbps
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