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7206 w/serial int. ext. drop insert voice data on p2p t1 replacement

Level 1
Level 1

I currently have a 7206 w/11 point to point

t1's connect via external csu/dsu to serial interfaces on router. Six connections are shared t1 w/voice and data using external Drop and Inserts, the other five are strictly data. The voice channels are connected to the external csu/dsu addrop via an amp connector to the main PBX and the data via a v.35 connector to serial interface on 7206. I've been told the 7206 is eol so Im looking to replace it. Any suggestions?

7 Replies 7

paolo bevilacqua
Hall of Fame
Hall of Fame

The 7206 is not EOL. You can do add/drop with the 7206, you need a VXR chassis, a recent NPE (300 or better) and the MIX enables T1 cards like PA-MCX-8TE1.

You can also user smaller ISR routers like the 38xx to replace the external add/drop DSU, and put the basis to integrate VoIP using the same hardware.

All really depends on where you want to go.

Im thinking the 38xx is probably where we should go and I've looked at the vwic2-2mft-t1/e1 but my telco and i are scratching our heads as to how to connect to the pbx?

The 38xx is a bit limited as density because you would require five of vwic2-2mft-t1/e1 to cover the fives sites that multiplex voice and data on the same connection.

How would you wire this, it is simple, take the RJ45 from the T1 circuit to card port 0, configure channel-group for the timeslots that are data and are terminated in the router. Configure tdm-group for voice timeslots and cross-connect to port 1. This port you connect to the PBX.

Repeat for as many circuits needed. I'm omitting some details like clock but there is plenty of documentation about this on CCO.

Note that a 7200VXR would require probably just one PA-MCX-8TE1, because you can aggregate multiple timeslots coming from different circuits into 1 or 2 T1s going to the PBX. That would require PBX reconfiguration.

Hope this is useful, if so please rate post.

Ok thanks. You've confirmed my suspicions about the t1 to port 0 then port 1 to pbx. I was hoping there was a way to remap multiple voice slots to one or more T1 ports back to the pbx using some interface in the 38xx chassis.

In fact you can do what you said above with a 38xx, by terminating also the voice timeslots in the router. The VWIC allows a mix of voice and data timeslots in the same interface.

You would use an all "dial-peer pots" configuration. You still would need PVDM (codecs) in the router, but much less T1 interfaces. All this would be totally transparent to the PBX.


I like the idea of conserving the t1 interfaces on the PBX and I believe our telecom people would be happier too especially the "totally transparent to the PBX" part. Our telecom people are getting a real kick out of watching me flounder around in their world. I'll start researching the PVDM codec stuff now.

Thanks again.

Hello again,

when I began answering this thread I was under the impression that 28xx and 38xx didn't supported TDM switching intra-module. I realized to be wrong when I ran across this document:

It is about ISDN but I think the drop & insert apply for static T1 TDM also.

Hope this helps.

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