Video Conferencing: Now a Much Easier Option

by Joe Chow

The video conferencing equipment can be cataloged into two types. One is desktop level device for very small group of participants, and web cam is one commonly used device under this category. The other type of video conferencing device is more advanced and sophisticated, and we usually called this video conferencing equipment as "Room System".

There are two kinds of connections for video conferencing. They are ISDN and IP network. ISDN uses digital telephone line while IP uses computer network, and they have irreplaceable characteristics. ISDN line is dedicated and more stable when compared to the IP network. However, the charge for ISDN network is quite high for overseas connection, for example, 384Kb/s speed to the U.S. needs about $3,600 per hour. Video conferencing parties are normally required to have the same connection type, so if one party provides ISDN connection and the other one does not have ISDN line installed, then an "ISDN gateway" will be necessary. In the CityU, this "ISDN gateway" was installed in the CSC computer room. When video conferencing equipment on campus that supports IP network connects to this gateway, it "translates" the traffic to ISDN. As a result, all rooms on campus basically support the ISDN connection. In spite of this, a direct connection using ISDN line is preferred as it is believed a certain downgrade of the video quality will be encountered if via gateway. This is the reason we encourage colleagues to use the designated rooms for video conferencing. There are at least 5 rooms on campus that can perform the suit the video conferencing function. They are either permanently equipped with video conferencing equipment, or can be set up for video conferencing within a short time. The rooms are listed in the following table.

The CityU, together with other tertiary institutions in Hong Kong, owns a multi-point conferencing unit called Accord MGC-100 MCU. With this device, it is possible for 8 participants to join in the same video conferencing session. However, advanced booking with other institutions is required. If the number of participant is less than four, CityU has its own multi-point units that can meet such need.

Some video conferencing sessions may need to use computer output. Most of the equipment we have in CityU is capable of supporting the transmission of video, sound and computer signals. This makes remote lecture possible as documents and computer slide shows can be displayed to the remote parties.

Availability Video Conferencing Room

There are 5 well-equipped video conferencing rooms that the CSC may help to accommodate your need, and you may find the details in the following table:


(no. of participants)

VC equipment Most suitable functions
Room N, CSC 1-100 PolyCom FX
(IP and ISDN)
- a Room System
Dynamic set up suitable for all conferencing functions
Room P, CSC 1-50 PictureTel 9000
(IP and ISDN)
- a Room System
Most suitable for remote classes
Room Q, CSC 1-38 PictureTel 9000
(IP and ISDN)
- a Room System
Most suitable for remote classes
Multi-Media Conference Room (FMO provides room supported) 1-100 PictureTel 4500 unit (ISDN only)
- a Room System
Small or large meeting and seminar
Board Room, 6/F CYC Building (MB provides room support) 1-30 Tanberg 880
(IP and ISDN)
- a Room System
Depends on the room's set up
Other conference rooms Vary Tanberg 880
(IP and ISDN thro' ISDN Gateway)
- a Room System
Depends on the room's set up
Your desktop 1-2 PolyCom ViaVideo
(IP or ISDN thro' ISDN Gateway)
*Available for short-term loan
- a desktop level device
Small video conferencing functions

Figure 1. Rooms and Facilities for Video Conferencing in CityU

Making a Booking

To book for the video conferencing service, you just need to submit a CSC Work Request Form through your departmental network administrator. Or you may simply contact our Help Desk (2788-7658) for more information. No student can make booking directly.

Things To Ask the People at the Other End

You should ask the people who you are going to work with:

  • the type of equipment that they have (Manufacturer and model type). This information is especially useful to us if the equipment they use is of older model, and certainly more effort will be needed to work things out.
  • a voice telephone number for their room. This is likely to be a telephone inside their control room, so that we can discuss any problems with their technical staff at the far end.
  • the number (ISDN number or IP address) for their video conferencing equipment, even if they are making the call, in case we have initial connection problems. If the call doesn't work from one end, it sometimes may work from the other. Unless the 'phone bill' is a real sticking point, this measure can solve the problem if we are running out of options.

In order to play safe, it is always recommendable to carry out a test call before the actual conference takes place.

Our Information for the Other End

Our ISDN numbers are: 3 lines starting with (852)-23194055

IP address: vary for different rooms

Room Layout

You can decide some table layout as well as the camera position. This will probably be decided before or during the test call.

Test Call

Video conferencing equipment is still not as compatible as it might seem, and it makes sense to check that everything works before conducting an important session. A test call is made with a technician in attendance and should precede the real call by at least several days. All aspects of the call should be tested, especially those involving computer equipment. It should be noted that the resolution of TV system, even of the highest quality, is still much lower than that of a standard PC screen. A test call will be unnecessary only if a call has been made before to the same place using the same equipment.