A friend of mine in New Brunswick sent me a picture of this Aastra Nortel M5316 Centrex telephone at his office.
This set is a copy cat of the M2616 PBX telephone, but it’s an analog/digital hybrid P telephone which means it only works on Meridian Digital Centrex either a Nortel DMS 100, SL-100 or the Genband C20.
These sets bring multi-line functionality to your desk without having a dedicated PBX at your office. The telephone company maintains the programming and administration of the buttons and lines. You could monitor busy lamp fields of different individuals in the network without any on premise equipment. So you could monitor lines of people across the state or town as long as they were tied into the same centrex network. At a time this was very convenient for offices that didn’t want to spend money on a private pbx. Now this concept can easily and inexpensively reproduced even in someone’s home via an IP-PBX.
The phones exterior was updated in 1996 from its former boxy Delta styled look to the Aries II look.
Common in many universities, hospitals and banks, these phones are workhorses and are still going to be around for a while, as they are still in demand and manufactured new by Aastra Mitel. Also, Genband, the company that won the auction on the carrier grade Nortel hardware, fully supports the Nortel M5000 telephone series call processing hardware on their C20 soft switch.
Places I have personally still seen these phones running are Harris BMO Bank, All of the City of Chicago offices, University of Illinois Chicago, Amtrak Union Station Chicago, Purdue University West Lafayette, Chicago Cultural Center, Chicago Public Libraries, The desk of Indiana Governor Mike Pence, various offices in the US Capitol, the desk of Canadian Prime Minister Justin Trudeau, and Illinois Secretary of State Offices.
And how can you tell the difference between these and a M2616? The Centrex M5316 phone has a yellow dedicated Mute button on the top right auto dial button.