[Asterisk-Users] TDM-400 doesn't detect far-end hangup

[Rich Adamson]

Stephen Bosch wrote:
> Hi:
> 
> I'm using a TDM-400 to terminate PSTN lines at my Asterisk server with
> kewlstart signalling.
> 
> When an outside caller calls the server, the TDM-400 goes off-hook and
> provides a ringing tone to the caller. If the caller hangs up before the
> receiving party answers the phone, Asterisk fails to detect the hang-up.
> The TDM-400 stays off-hook, hogging the line, while Asterisk rings the
> extension.
> 
> I thought the TDM-400 FXO module was supposed to detect far-end call drops.
> 
> Is there something I need to configure to make this work?

I'd first check to see if you are actually getting a disconnect 
indication from the pstn line. In North America, the disconnect can be 
seen with an ordinary voltmeter across tip-ring as a voltage drop (to 
zero) for about a 1/4 second. It usually occurs from 1 to 5 seconds 
after the pstn caller has hung up.

If you don't see that disconnect, then the issue is related to your pstn 
provider not providing it to you.

If you do see that disconnect, then you've got something misconfigured 
in asterisk.