chan_isdn & single digit extension

Hi all,

I do have a quite urgent problem. I have setup an Asterisk 1.4.22 with mISDN 1.1.8 and a HFC-S PCI card. Everything is working fine, beside one issue:

Here in Austria, the telco sends in PTMP mode only the dialed extension and not the complete number on ISDN, therefore I just listen on that. If nothing is dialed, chan_misdn sends the caller into ‘s’, but that happens also if only 1 digit is being sent - in my case 4 is the old fax extension and all faxes go to the operator at ‘s’. It seems that in the chan_misdn code, at least two digits must be there otherwise ‘s’ is sent. I did not find the lines where this happens. Can anyone tell me who to solve the issue or where the lines are which must be changed.

Here’s the log:

P[ 1] I IND :NEW_CHANNEL oad:1279373737 dad:4 pid:17 state:none
P[ 1] Chan not existing at the moment bc->l3id:2001c bc:0x6dd560 event:NEW_CHANNEL port:1 channel:1
P[ 1] I IND :SETUP oad:1279373737 dad:4 pid:17 state:none
P[ 1] read_config: Getting Config
P[ 1] I SEND:PROCEEDING oad:01279373737 dad:4 pid:17
== Starting mISDN/1-u37 at from-outside,4,1 failed so falling back to exten ‘s’



Ok at the asterisk CLI what does show dialplan from-outside tell you?

You need to add an extension 4 into that context.


Thx for the hint, but I’ve a extension 4 in my dialplan. It seems that any single digit extension produces that error at the time before a dialplan is accessed. The error results from the chan_isdn and not from the dialplan.

any other ideas?

At the s extension try and NoOp all the CALLERID variables that are available:

etc… have a look in the doc directory what the others are. It’s been a while so it’s not fresh. Hopefully, the caller id is being preserved, then you can send it to another extensions - e.g.

s,1,NoOp( The caller id rdnis is ${CALLERID(rdnis)} )
s,n,NoOp( The next caller id variable is …)

12345678904,1,Fax(…and handle the fax however you would)

Hope it makes sense to you, and I hope it gives you some clues,


There is this error “from-outside,4,1 failed so falling back to exten ‘s’” so I wanted to see what you are trying to do that makes it fail. hence show dialplan from-outside

without showing us anything it not possible to help.