CAS to FXS on Cisco 2851

Unanswered Question
Apr 1st, 2009


When there is an incoming E1 R2 CAS call directed towards an FXS, the call does not complete. The cisco does collect the digits on the incoming side (CAS) but does not send it to the FXS. Is there any specific configuration that needs to be done for this?



I have this problem too.
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ashwin_k_kumar Wed, 04/01/2009 - 18:28

The E1 R2 config is as below

controller E1 0/3/1

framing NO-CRC4

clock source line primary

ds0-group 12 timeslots 1-12 type r2-digital r2-compelled

cas-custom 12

country brazil


release-guard-time 500

category 2


answer-signal group-b 1

ani-digits min 7 max 11

ashwin_k_kumar Thu, 04/02/2009 - 15:26

Thanks for the reply.

I tried that but there was no difference.

What I did now was to make


All of this on the same box and I still see the problem.

Am atatching the logs for this.

Nicholas Matthews Thu, 04/02/2009 - 17:58

Well this doesn't look good:

2 22:37:20.302: [0/3/0:12(1), R2_Q421_IC_ANSWER, E_DSP_SIG_0000] -> ERROR: INVALID INPUT

Then it looks like a few seconds into the call 0/0/0 hangs up:

*Apr 2 22:37:26.894: htsp_process_event: [0/0/0, FXSLS_CONNECT, E_DSP_SIG_0100]fxsls_offhook_onhook, HF duration Max=1000, HF duration Min=150


ashwin_k_kumar Thu, 04/02/2009 - 18:41

I dont know what this means


The terminator never rings. Any options of what could be wrong and how we can go about this?

Nicholas Matthews Thu, 04/02/2009 - 22:36

Hi Ashwin,

I'll be honest - I don't have all of the E1 R2 states and ABCD bits memorized. I usually have to stare through lots of examples and documentation to figure out each state.

You may want to start here:

This page has some of the bit tables required:

Best of luck!



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