Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

Legacy Voice/Data Multiplexing

Has anybody had any experience of muxing legacy voice from a PBX and data from an X21 source over a single 2mb leased line. Looking at the spec for the VWIC-2MFT-G703 card it appears to fit the job but I can't find config examples on CCO. I do not want VoIP just old fashioned TDM voice and data.


Cisco Employee

Re: Legacy Voice/Data Multiplexing

You can generally emulate a T1 between PBXs by using TCCS:

Use clear channel codec and it should work. You will also be positioned for VoIP with thsi if you ever decide to go that direction.

New Member

Re: Legacy Voice/Data Multiplexing

Not sure it is what I am looking to do, basically just wanted legacy multiplexing for x.21 data and e1 voice over a leased line between 2 sites.


Re: Legacy Voice/Data Multiplexing

Use a drop and insert VWIC . There is a little more info here -

Basically you can configure one port to TDM cross connect a group of timeslots to other timeslots on the second port. You have one group reservedfor pure tdm and more timeslots set up as a channel group for the data.

Here is a basic example -

controller e1 0/0

description - connection to PBX

clock source internal

tdm-group 0 timeslots 1-10


controller e1 0/1

description - connection to WAN E1

channel-group 0 timeslots 11-31

tdm-group 1 timeslots 1-10

interface serial 0/1:0

ip address

cross-connect PBXLink e1 0/0 0 e1 0/1 1

this will connect the first 10 timeslots from e1 0/0 to the first 10 timeslots of e1 0/1 , timeslots 11-31 on e1 0/1 will be used for data between the routers.

The other side would have matching configs

CreatePlease to create content