asterisk users - Jan 2006 - shared fxo line

My home asterisk system has failed the wife test (still too much echo
with the current hardware... my voice seems okay but when she talks she
complains of echo), but I'd still like to be able to use it to send and
receive fixed line sms messages to and from my mobile.

My x100p card has 2 ports on it, a 'line' port and a 'phone'
port, so
there is provision there to plug the household phone into the phone
port, which is what I've done for testing.

Is this generally held to me a good idea? How will asterisk cope with
it? My dialplan is:

[fxo]
exten => s/0198339100,1,Goto(sms_rx,s,1)
exten => s,1,NoOp()
exten => t,1,NoOp()

[sms_rx]
exten => s,1,Answer
exten => s,2,Wait(1)
exten => s,3,SMS(${CALLERIDNUM},a)
exten => s,4,System(/usr/local/bin/sms_rx)
exten => s,5,Hangup

fxo is the default context of my x100p
0198339100 is the number of the sms message center
/usr/local/bin/sms_rx is a wrapper script to mail the sms message to me

This seems to work okay for incoming calls, Asterisk doesn't answer the
phone unless the call originates from the sms message center, which is
what I want. Without the 's' and 't' NoOp() calls, asterisk
complains
that it doesn't know what to do with the call.

The only thing I can think of that might cause problems is if Asterisk
tries to send an sms while someone else is using the phone line. Can
asterisk detect that the line is otherwise not in use, eg take phone off
hook, detect dialtone, fail if no dialtone?


Sound good? Anything else that might bite me?

Thanks

James

> The only thing I can think of that might cause problems is if Asterisk
> tries to send an sms while someone else is using the phone line. Can
> asterisk detect that the line is otherwise not in use, eg take phone off
> hook, detect dialtone, fail if no dialtone?
asterisk doesn't detect dialtone at all, AFAIK

It doesn't work well with other things like phones on the same line,
but if you have it set to ignore calls, that won't be a problem.