Help with SIP Phone Conference Calling

Here is the quick version of my issue. We currently a number of Polycom IP 450s hooked up to our Elastix box. The phones will not allow a 4th person to be added to a 3-way call. The conference button dissapears from the Menu. I have contacted Polycom and they said it is not a limitation of their phone and to contact my SIP provider. I contacted them, and they say that we are authroized for 4 outbound channels with bursting available as needed. So I should be able to make a 5-way call. I now turn to the Elastix box to see if there are any issues here, but I have not been able to find anything in the literature or wiki regarding altering the maximum number of simultaneous calls from a single SIP Phone. Can anyone here provide help / advice in this regard in tweeking the Asterisk portion of our Elastix box?

Asterisk doesn’t really distinguish between trunks and phones. If it imposed a limit, by default, it would make trunks unusable.

There are mechanisms to limit the calls to or from a device, but these have to be explicitly enabled.

Is the phone on the latest firmware? It sounds more like a phone problem than anything if the conference button displayed disappears after you have connected that number of calls.

Hello jpisani,

from our UCS 3.3.0 Admin Guide (page 4-12)

[quote]All phones support three-party local conferencing. The SoundPoint IP 450,
550, 560, 650, and 670 phones may support four-way local conferencing.

Four-party conferencing requires a license key for activation. For more information,
refer to Manage Conferences on page 4-22.

Best Regards

Steffen Baier

Polycom Global Services