Lucent/Nokia DDM-2000 OC-12 Multiplexer Help

I have a legacy Lucent DDM-2000 OC-12 Multiplexer. I would like to use this as a test bed in my lab. I’m trying to figure out how to setup this device and communicate to it via serial connection. I’ve read most of the online manuals and I think I’m doing all the right things, but still unable to talk to it. I believe my system may need some software since I get the letter ‘d’ in the 7-segment display on the BBG8B Sysctl card.

Thanks to anyone that may have some insight to this device or connection to someone who may have insight to this device.