The 79xx phones don't support it. But... theoretically, you could do something LIKE a push-to-talk. They support auto-answer, and they also support PLAR (private line auto ringdown, aka hotline, where the moment you pick up the phone it dials a pre-defined extension.) It would be a 1-to-1 push-to-talk, and it wouldn't exactly be push-to- talk, but in theory... (note: theory often differs from reality in practice.) There's also the telnet administration interface on some (all?) versions of the SIP software load, which if enabled (and you have the password) makes it possible to send out-of-band commands the phone to press any button combination, which is a really ugly hackable interface. The real answer would be to get phones from a company with a development effort that is concerned about SIP. The 79xx series traditionally has not cared about SIP, and has focused on CCM in all of it's proprietary nonsense. Linksys/Sipura did a far better job doing the "right thing" with SIP than traditional Cisco ever did on the desktop, and that rift still shows today despite being (now) the same company. JT On Nov 15, 2009, at 8:43 PM, Scott Berkman wrote:
The "original" Cisco phones (7940, 7960, 7905, 1912) that have official SIP support have never had any advanced features (namely subscribe, presence, answer-after, etc) to the public SIP firmware. Some of these features are supported with varyingly proprietary SIP functions on the CCM SIP versions of the Firmware. Using these with other platforms is possible, but is neither supported or documented in any official capacity. You can find some basic instructions out there if you feel like wasting a lot of time on the project, but I'm not sure that all of the functions have ever really been figured out from a provisioning standpoint.
That being said, PTT is possible on any phone with the right feature platform in some manner. For instance, BroadSoft implements PTT outgoing using a star code, which could be auto answered by a different phone that does have support for the answer-after tag. A PTT call to one of these devices would just ring in like any other call however.
The Cisco/Linksys/Sipura SPA series of phones has a similar design and a much more full list of supported features. There is also a new line of Cisco multi-media phones (9X00) that may or may not have this type of support, but does advertise SIP interoperability with "partner" platforms. I don't know much about them beyond that.
-Scott
-----Original Message----- From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org ] On Behalf Of Alex Balashov Sent: Thursday, November 12, 2009 9:51 PM To: Ujjval Karihaloo Cc: voiceops at voiceops.org Subject: Re: [VoiceOps] Cisco 7940 PTT
No.
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On Nov 12, 2009, at 9:30 PM, Ujjval Karihaloo <ujjval at simplesignal.com> wrote:
Can a Cisco 7940/7960 do Push to Talk..any config suggestions?
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