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Making & Receiving Video Calls

If you have a video desk phone, the Jabber soft client, or a video conferencing unit registered to the University phone system, it is possible to make and receive video calls to people outside the University phone system.

We support H.323 & SIP protocols over IP. From informal discussions, very few people use ISDN for video calls, so we do not have this facility. If you feel you have a pressing need to make or receive video calls via ISDN, please let the Telecoms Helpdesk know.

Making Calls

URI Address

A URI address looks very much like an email address. e.g. 37070@cam.ac.uk. To call this type of address, just dial it! This is easiest on the Jabber soft-client, but some of the Cisco handsets (e.g. 8851, 9951) can dial these address from the keypad. To be able to dial letters or symbols, go off-hook, and then look for the "ABC" soft-key.

IP Addresses

Dialing an IP address requires a little bit more work. Firstly, you have to change all the dots in the address to "*". Then you have to prefix this new string with "140".

e.g. The Janet Video Conferencing Service Bridge is at IP Address 193.60.198.133. To call this you would dial 140193*60*198*133

Receiving URI Calls

To receive calls, your phone number needs to have a URI set. If you have access to admin.phone, you can check if this is set by looking at the "URIs" tab in extension details. Currently, only the Telecoms Helpdesk can set URIs for extensions. Only extensions can have URIs: Hunt Groups cannot have URIs.

Once a URI is set, the far end can just call that URI. e.g. 37070@cam.ac.uk

Receiving IP Address calls

Devices connected to the University phone system can not directly receive calls to their IP address. For outside systems that cannot call a URI, the caller must call the University at either 131.111.110.14 or 131.111.110.84. The caller will then be connected to an audio auto attendant where they can enter, via their key pad, the 5-digit extension number of the video unit.