[cisco-voip] CallerID on *FXS* Port with MGCP

[Robert]

On Tue, 2007-11-06 at 13:50 -0500, Wes Sisk wrote:
> One final comment, you can track this feature under defect CSCdu45646.

I'm not sure if this is related to the FXO issue or not, but...

I tried to use an FXS port (in a 2811) for paging at a recent
installation. We generally use an ATA port connected to a Bogen TAMB,
which is in turn connected to the paging system. I supposed that using
an FXS port would be equivalent, but the FXS port sends the CallerID
data burst (destined for telephones that support CallerID) between the
first and second rings, then cuts the bearer audio through. The TAMB
answers immediately on the first ring. The net result is that the caller
dials the paging DN, hears a confirmation tone, but the announcement is
not connected immediately to the paging system. On the paging speaker
end, the speakers give the attention tone (generated by the TAMB), a
raucous racket (the CallerID data burst) then the callers announcement
is joined in progress. This occurs regardless of the settings in CCM
Admin or from configuration on the 2811 itself.

I found a matching description in TAC Case Collection where the issue is
that, when running the gateway in MGCP, some of the CallerID parameters
are not communicated correctly or something like that. The net effect is
that disabling CallerID in CCM does not actually disable it on the
hardware. The work around was "wait for 2nd ring before answering" which
is not practical for the paging application, so I put it on an ATA-186
anyway.

Robert