From FB group Bell Telephone
Ohhhhh, Ed Vaughn, you gave me a big headache. Those message waiting lights…
We had a 1200 baud MW line directly from the CO to our PBXes, and one PBX then distributed it to dozens of others in the district over the network, not by ethernet, but by XNS over a VPN. It was amazing how fast others would complain when the silly little light didn’t work. See, everything else would be wonderful but something would happen with the 1200 baud link, the ‘master node’, the XNS, the VPN or any two or more of them after an “event” such as a long power outage. Oh, what a headache! I’m relieved we of got rid of it with the VoIP.