I have a pair of TSU 120 units connecting two PBX systems together over a T-1 span. The first 18 channels are assigned to the DSX1 port. The last 6 channels are assigned to the data port for some data gear. I need to convert the PBX signaling to ISDN (17B+D) and use the 18th channel for common signaling (D-Channel) for just the DSX1 port. The channels for the data port need to stay the same with no changes in anything. Is this possible and do I need to make any changes in the TSU120?
This is possible as long as your PBXes can look to DS0 18 for the D-channel.
The only configuration change you may have to do in the TSU 120s is to make sure Robbed Bit Signaling is turned off on the DSX-1 port (Config > Port Config > 0.2 DSX-1 > ROB BIT SIGNL: Off)
If it is already off then there are no changes needed in the TSU 120s.
Thanks,
Patrick