[asterisk-users] What makes TDM400 FXS Connection to TELCO go into Off Hook State?

[Tzafrir Cohen]

On Mon, Nov 10, 2008 at 07:34:34PM -0500, Jim Duda wrote:
> I've been having trouble with making outbound calls to my 
> TELCO from a TDM400 card (FXS KS signalling) after upgrading
> from 1.6-beta9 to 1.6.0.  The problem is completely intermittent.
> 
> When it fails, I get this message:
> [Nov  9 19:12:26] WARNING[18916] app_dial.c: Unable to create channel of type 'DAHDI' (cause 0 - Unknown)

Can you enable debug logging? Do you see any message about the casue for
that?

> 
> At some point, it starts working, but I don't know what is 
> triggering asterisk to start working.  But I have a theory below.
> 
> I have instrumented the code with debugging and narrowed it 
> down to some code in chan_dahdi where it appears to be checking
> for hookstate.  I can actually resolve this issue by changing
> a return code in the available function in chan_dahdi.c
> 
> This led me to look at dahdi show channel 4
> 
> It appears that when outbound calls are working, 
> the Hookstate displays Offhook.
> 
> It appears that when outobund calls are not working,
> the Hookstate displays Onhook.
> 
> Can anyone tell me what the normal state of an FXS line attached
> to a standard TELCO should be when no call is in progress and
> when a call is in progress?
> 
> Can anyone tell me what causes an FXS line attached to a
> standard TELCO to transition to Off Hook state?  It seems
> to me that the state would transition between off hook and
> on hook as a call is in progress or idle respectively.
> 
> Thanks,
> 
> Jim
> 
> asterisk*CLI> dahdi show channel 4
> Channel: 4LI> 
> File Descriptor: 21
> Span: 1
> Extension: 
> Dialing: no
> Context: incoming
> Caller ID: 
> Calling TON: 0
> Caller ID name: 
> Mailbox: 100
> Destroy: 0
> InAlarm: 0
> Signalling Type: FXS Kewlstart
> Radio: 0
> Owner: <None>
> Real: <None>
> Callwait: <None>
> Threeway: <None>
> Confno: -1
> Propagated Conference: -1
> Real in conference: 0
> DSP: no
> Busy Detection: no
> TDD: no
> Relax DTMF: no
> Dialing/CallwaitCAS: 0/0
> Default law: ulaw
> Fax Handled: no
> Pulse phone: no
> DND: no
> Echo Cancellation:
>        128 taps
>        (unless TDM bridged) currently OFF
> Actual Confinfo: Num/0, Mode/0x0000
> Actual Confmute: No
> Hookstate (FXS only): Offhook --> Working State
> 
> 
> My chan_dahdi.conf:
> 
> ;[pstn]
> mailbox=100
> mwimonitor=fsk
> mwilevel=512
> mwimonitornotify=/usr/local/sbin/zapnotify.sh
> faxdetect=incoming
> signalling=fxs_ks
> context=incoming
> callwaiting=yes
> callwaitingcallerid=yes
> echocancel=yes
> echotraining=no
> echocancelwhenbridged=no
> channel => 4
> 
> ;[fax]
> ; FAX machine connected here
> faxdetect=no
> signalling=fxo_ks
> context=internal
> channel => 1

-- 
               Tzafrir Cohen
icq#16849755              jabber:tzafrir.cohen at xorcom.com
+972-50-7952406           mailto:tzafrir.cohen at xorcom.com
http://www.xorcom.com  iax:guest at local.xorcom.com/tzafrir