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New Member

T1 CAS Pulse dialing

We've ran into a situation at a customer site where the carrier can only provide a T1/CAS circuit with Pulse, not DTMF or MF. TAC is telling us that Cisco for the most part does not support Pulse dialing.

We are looking for a way to convert Pulse to DTMF or MF either with our current Cisco gear (2821 Router gateway with VWIC2-2MFT) or 3rd party converter.


Re: T1 CAS Pulse dialing

You might be able to check with AdTrans... they are the only ones I can think of that may have a product for this. You might be have to ditch the T1 line and move to analog then. Your only other option, is to use the CAS T1 line, have every call routed to Unity CallHandler.

Then have the call handler:

"You have reached Company XYZ, for the directory, press 1, you may dial an extension at any time"

Might work, but not sure with pulse. worth a shot if you are in a pinch

New Member

Re: T1 CAS Pulse dialing

did you find a solution to this problem, as i've just ran acrossed the same issue.

Hall of Fame Super Gold

Re: T1 CAS Pulse dialing

Honestly I find very hard to believe that pulse-only T1 trunks can exist in North America.

Cisco Employee

Re: T1 CAS Pulse dialing

The IOS CLI parser will give the option of pulse dial for a T1 CAS voice port, but it doesn't work. It's a left over from analogue E&M and FXS/FXO configuration.

It's more likely the carrier doesn't want to convert their trunk to DTMF operation rather than they don't support DTMF operation.

DTMF has been used since the early 60's, far longer than T1 services. Any carrier would know the advantages of DTMF operation over legacy pulse operation. Likewise any central office would have the capability of DTMF operation. Do you really think they would stay in business if they told all their analogue trunk customer they must use pulse dial operation, thereby preventing them from using phone banking, IVR and all other DTMF based applications!

Pulse to tone convertors are available, but past experience with an FXO based unit (before it was smashed into small pieces and set on fire) was they were a complete and utter waste of time and caused no end of problems due to picking up noises that 'sounded' like pulses and then playing out in band DTMF tones. For T1 operation it is slightly different because the pulses are sent via the ABCD bits, perhaps some company makes a T1 based model.

Your best bet here would be to go the service provider and use the line we get fed here in the TAC when a customer is not happy - "I want this escalated". It sounds like you are paying good money for an inferior service.

Hall of Fame Super Gold

Re: T1 CAS Pulse dialing

I agree with all what Paul said above, however in fact a telco supporting pulse dialing only would not prevent use of IVR, banking etc.

All what the subscriber would do is move the phone pulse/tone switch to tone after the call is completed, then put it back.

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