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New Member

R2 progress tones

In R2 signaling, who is responsible for in-band progress tones (busy, ringback)?.The router or the PBX?


Re: R2 progress tones

It depends on the direction of the call. If the router makes the call to the PSTN/PABX, then the progress tones would have to come from the external device to give an indication of the call state. Ifg the router accepts the call from the PSTN/PBX, then it will have to generate the tones in band towards the caller to let them know the state of the call.

Depending on the progress tone, the router can determine what is happening with the call. If the remote device returns a busy/subscriber out of order, this can be mapped across to a VOIP clearing code, likewise the R2 answer signal is seen on the router as a Connect,

New Member

Re: R2 progress tones

1. Then,in R2 signaling, when the router call the PSTN/PBX it must provide voice cut through for in-band tones (busy, ringback, congestion)?

2. Why the bug CSCdw00013 says that the router does not provide busy tone when a b-3 is received from PBX?


Re: R2 progress tones

Yes, the router must cut through the audio path to allow the caller to hear any downstream progress tones.

Will have to look up this bug to see what condition it relates to - check the postings tomorrow.