[Asterisk-Users] GSM gateway for Asterisk

[Bill Michaelson]

I recently obtained a FCT-11M GSM-analog converter box.  It arrived with 
no documentation.  So I popped in a SIM chip, and connected the the RJ11 
port to an FXO port on my Asterisk box.  It worked smoothly right away 
for inbound and outbound calls in all respects.  For about an hour.  
Then either spontaneously or due to some action I've been unable to 
identify, call supervision and other functions became flaky.

First, I noticed inbound calls started malfunctioning.  The Asterisk box 
answers, but no audio is heard on either end (the dialplan bridges to a 
SIP phone).  Also, the call never ends.  I can only knock it down by 
using CLI soft hangup or restarting Asterisk.

Then outbound calls got wierd.  It will dial out thru the GSM network to 
my cellphone, and audio is OK in both directions, but call termination 
fails if initiated from the remote GSM side.  In that case, the box 
emits three short beeps, followed by a steady beep which is audible on 
the SIP phone to which the call is bridged.  The channels don't hangup 
until the SIP phone causes it to.

I was initially concerned that I had fried the FXO port by using an 
incompatible device, but I've ascertained that the port still works OK 
with a POTS line.

I now suspect that the FCT-11M has been reconfigured somehow, since I 
obtained it and it was working.  But I have no clue about how to examine 
it's configuration if possible at all.  It has a USB (master) port but I 
don't know what it is for.

Does anyone know if English documentation is available, or otherwise 
have any ideas on how to debug this?  Much appreciate any insights.