[Asterisk-Users] Limiting incoming SIP calls & Original CallerID on transfer

[Paul Liew]

From: "Erik Barker" <erikb at netnation.com>

> We are currently using Polycom IP600 VOIP phones for our office which
> are capable of handling 2 calls per SIP registration. What we're finding
> is when staff are on the phone, Asterisk will pass them a second call
> which will show up on their display, and an audible beep is heard over
> the phone (regular call waiting). I would like to limit the number of
> calls sent to each phone to 1 call only; otherwise respond as being
> busy. I have looked at trying to accomplish this in the sip.conf by
> using the 'incominglimit' and 'outgoinglimit' parameters, however, the
> only one that *seems* to work is the 'incominglimit'. This prevents
> further calls from reaching the phones, rings busy, but does not allow
> our phones to initiate a 2nd call OR transfer their existing call. The
> 'outgoinglimit' parameter does not seem to have any effect on limiting
> whatsoever. Is there a way to limit calls passed to the phones from
> Asterisk and also allow each phone to initiate 2 calls or transfer calls
> (disable call waiting)??
>
> I have also looked at the WIKI for the parameters listed above and it
> *appears* that 'outgoinglimit' should do what I want, however it also
> states that this function has been disabled??
>
> "The _outgoinglimit__ is currently disabled in the source code of the
> SIP channel."
>
http://www.voip-info.org/tiki-index.php?page=Asterisk%20sip%20incominglimit

Hi to all,

Sorry for not responding a lot earlier to the issue of incominglimit as I
have been absolutely flat chat, no excuses however, hope I can shed some
light on this issue. When I first worked on this, "incominglimit" and
"outgoinglimit" was already in place, but it didn't work in preventing call
waiting at all. Customers of ours were on GS phones, and all of you know the
problem with that on call waiting. The trouble is, with call waiting you
can't really separate incoming and outgoing cleanly. The main aim was to
prevent call waiting whenever the phone was in use (it should be changed to
"inuse" as in the CLI command "sip show inuse") whether on an incoming or
outgoing call. Once you separate the two functions, call waiting will fail,
ie when on outgoing call, the incoming counter will not increment, therefore
you WILL receive an incoming call and vice-versa. I know that what I've done
is not pretty (ie to incorporate the two into one), but it does fix the
problem with call waiting on SIP phones that can't or won't handle it. I am
open to ideas or suggestions and will put in the time to fix this properly
once an for all. Please reply either on or off list.

Paul