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PRI access circuit for frame relay

Has anyone used a PRI access circuit for frame relay? In some instances a network design calls for the use of a drop and insert CSU/DSU to pass unused access channels to a PBX to carry voice. This works just fine when the acess circuit signaling is CAS, but does it work the same when the signaling is sent across a D-channel? Because the CSU will be responsible for encoding the received data from a V.35 interface onto the access circuit, I imagine it will be a function of the CSU/DSU? Typically the D-channel gets mapped to the PBX to provide enhanced/extended detail of inbound and outbound calls, ANI as an example. If I map the D-channel to the PBX will there be an issue combining both voice and data across a PRI access circuit?

Community Member

Re: PRI access circuit for frame relay

The PRI can be provisioned to support both voice and data. Cisco supports this on thier ASAP (any service any port) gateways such as the 5350 and 5800.

Cisco Employee

Re: PRI access circuit for frame relay

As long as you map the D-channel all the way through, you can pretty much do whatever you want with the rest of the channels and they should be transparent.

I don't know how a router would fit into this scenario, but you could do the following:

channels 1-8 as PRI B-channels for voice

channels 9-23 for data

channel 24 is the D-channel

Assuming your CSU/DSU can handle this mapping, you should be OK.

In Cisco-ese, this can be done on a VWIC MFT interface.

Or, did I misunderstand your question?



Community Member

Re: PRI access circuit for frame relay

No, you understood my question. That's what I'm going to end up doing. I can send the D-chan out the DSX-1 port of a DSU and turn off rob-bit signaling.

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