T1 CAS to DMS-10 in rural area

Unanswered Question
Aug 20th, 2007

My rural customer cannot get a PRI from VZ in his rural area, so VZ installed a T1. I'm having trouble talking their language, but they said they are sending and expecting a wink, but they don't call it E&M. DTMF is configured. When I dial a DID that they are supposed to route to that trunk group, we get a fast busy. VZ says that fast busy is the current overflow setting. When I DEBUG VOICE VTSP ALL, I see no activity for any inbound calls. I have only a very simple dial-peer:

dial-peer voice 90 pots

destination-pattern 91T

port 0/0/0:0

prefix 1

...which should basically generate dialtone to VZ when the trunk is seized.

The controller is set up this way:

controller T1 0/0/0

framing esf

linecode b8zs

ds0-group 0 timeslots 1-24 type e&m-wink-start

Can you suggest some sort of debug where I can see the status of the trunks? Does anyone have any input into the configuration that may be specifically related to DMS-10 configurations? VZ says that this is a very old switch.


I have this problem too.
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kbyrd Fri, 08/31/2007 - 10:50

Thanks. I did try that with guidance from TAC.

We finally resolved the problem. VZ, the carrier, had another customer in Colorado that experienced the same issue with a DMS10 to Cisco router running T1 CAS E&M-Wink. They said to change framing/linecode to sf/ami from esf/b8zs. And believe it or not, that's what worked. (They changed it on the DMS10 side, too.)

I wouldn't have believed it had I not seen it myself.

Eric Knudson Sat, 09/01/2007 - 09:06

(looks like i'm a little late oh well ^_^)

You can try using a 'debug vpm signal' to see the state of the each ds0 as you execute a 'csim start xxxxxxxxxxx' to send calls to your cell or something.

It's been awhile since I've had to do any CAS troubleshooting, but post the debugs for an inbound and an outbound call and I'm sure we can help you out.

When I was installing in areas where I couldn't get a PRI sometimes I would an fxo-loopstart trunk.

check here for descriptions, 'wink' denotes E&M(there's ALWAYS the disconnect in nomenclature between us and the telco, though):


I think you can also use a 'debug vtsp dsp' (or whatever that was changed to - IOS might tell you that command is deprecated) to see the actual dtmf that's coming in/going out as well.


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