Help connecting Interalia XMU to an Option 81c AC system

[MrPederman]

I am trying to connect an Interalia system to an Option 81c AC powered system. I am using Interalias "Option 2" for a Nortel switch so I can have Pulse start Level return operation. I have connected this configuration on a DC powered Option 81c system and the -48vDC came from the PBX power, which gave me a commom logic ground( at least thats what I believe ). The AC system I have doesn't provide a -48vDC source, so I have an external -48vDC power supply. This is not working. I tried to ground the power supply to the PBX logic grounds and this didn't help. I appreciate any help.

 

[faelo]

We do the same with a Option 61C and a XMU+, the trick is to connect all the ports to the common ground.