[Asterisk-Users] Alarm panel through ATA

[Rich Adamson]

> I am trying to get some feedback from anyone who may have experience of 
> a problem I am having.
> We have several buildings that having only fiber to them so in order 
> that the alarm panel can call the central station, I have provided a 
> Sipura 1001 ATA. I can make a call to the central station through the 
> ATA, using an analogue phone.
> The alarm panel does not seem to function properly thorugh the ATA, 
> either it is not going off-hook properly or the ATA is treating the 
> modem tones as a fax, I am not sure what is happening. Does anyone have 
> experience of getting this to work?

Is the alarm panel truly expecting to use a modem to communicate with
central station?

If so, sip/rtp will not handle modems that attempt to use anything
greater then about 2400 baud. (Note: there is a diffence is the term
"baud" verses "bits/second". Newer high-speed modems use an encoding
mechansim that involves phase-shift technology to achive a higher
bit-per-second speed over a low baud rate. sip/rtp will not accurately
reproduce any modem signal that involves phase-shifting. The sampling
rate is not sufficient to accurately reproduce phase-shifted analog
signals.)

Also, in the sipura release notes (for v3.1.5) specifically
indicates they watch for fax tones and, more recently, modem tones.

.    Distinguish between FAX Passthrough mode and Modem Passthrough Mode.
     Modem Passthrough Mode can only be triggered by predialing the
     <Modem Line Toggle Code>. FAX Passthrough Mode is triggered by
     CED/CNG tone or NSE events. Echo canceller is automatically disabled
     for Modem Passthrough Mode only. Echo canceller is automatically disabled
     only if <FAX Disable ECAN> (Line 1/2) is set to "yes" for that line
     (in that case FAX passthrough is the same as Modem passthrough).
     Call-waiting and silence suppression is automatically disabled for
     both FAX and Modem passthrough as before. In addition, out-of-band 
     DTMF Tx is disabled during modem or fax passthrough (all audio are

The "Modem Line Toggle Code:" option appears on the Regional tab and
has a default string of "*99". Therefore, your alarm panel modem would
need to prefix its dialing with *99.

Might check those two items.

Rich