It is. Cisco does not officially support it... but it works... sortof.
I have tested it and 2 systems do not have any trouble calling eachother... but the dialplan is a bit odd. The 320 does not like dialing 3 digit external numbers.
Setting it up is as simple as adding a sip trunk on both devices that just point to eachother. No authentication. The hardest part is figuring out the dialing, if I recall, simply dialing a steering digit plus an extension number does NOT work for dialing phones on the other system.
I really wish Cisco would do something with this... its like 90% there... some small changes would allow full site->site sip calling without the limitations....
Actually if they could allow us to make custom Dial-Plans you could pretty much work it out and make it work
Although the maximum amount of sites talking back to a master system would be 2 (3 all up) which is not bad, but they could enable Site-2-Site and allow for up to 5-10 site to communicate.
An Ideal solution and Could have sold this scenario at least 10 times over already, they never had the budget for a UC-500 because their business was not big enough, and the UC-320 was ideal just lacking the ability.
Ended up getting beaten by an Asterisk system using IAX to communicate between sites, on a cost-for-cost comparison the Asterisk system actually comes out dearer, insane really.
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