[asterisk-dev] Implementing Paging on the Linksys SPA9XX phones

[Kevin P. Fleming]

John Lange wrote:

> Can you give examples of which phones? I don't know what you mean by the
> SIP/SDP model and google on those terms didn't turn up anything
> meaningful with regard to paging.

Snom, for certain, supports multicast RTP, but it has to be done using
the normal SIP/SDP method of sending an INVITE to the phone and telling
it what multicast stream it should listen to (and whether it should
auto-answer, etc.).

> It may be as simple as specifying what type of "paging" a given device
> supports (if any) in the config files for the device. If a given device
> is then included in a page group then asterisk would handle each device
> in its own way.

No, that is the simple part, because it's in the channel drivers.
Channel drivers don't know what 'paging' is, they only understand
channels, which can be attached to anything at all.

> So for example; SIP phones which only support paging because one of
> their lines is set to auto-answer (like the ciscos) can be one setting;
> phones that support multi-cast linksys style is another; SIP/SDP yet
> another; and so on.
> 
> We are very interested in solving this issue because paging seems to be
> the most often asked for feature in Asterisk that doesn't really exist.

It's not. The most asked for feature is key-system functionality,
followed closed by T.38 media gateway support. Doing paging the way we
do it now seems to work for many people.