What Are These Old Nortel Norstar Units I Found at Work?

You're correct about the smaller unit being the voicemail module. The larger one could be a main or expansion cabinet for a Nortel MICS or CICS system. If it’s still powered on, it might be connected to older devices like elevators or alarms. You can figure this out by simply unplugging it and noting if anyone complains. To access the configuration, you can use the Feature button along with a code from your handset. Also, if you happen to have any T1 cards, hold on to the instructions that come with them; they can be unique and helpful!

It’s likely a Nortel PBX system. Those were pretty solid at the time. The Flash module is indeed for voicemail, so don't throw away that power supply! The unit probably has some value if you're looking to sell it, and the wiring could be connected to handsets or even fax machines. Make sure you check for any lines that could be used by emergency systems before tossing anything out.

If you have any old handsets still in use, make sure you check them first. Norstar systems connect directly to the phone lines, and it’s usually alarms and elevator lines that are patched in separately. It’s good to find a punch panel where the telco lines meet to be certain of what you might need to keep. If you find that your phone lines are all managed through VoIP now, it might be safe to let these go.

Definitely check your documentation if you have any (good luck with that!). It's important to know if those units are still in use for anything critical, like alarms or elevators. I wouldn't remove them without ensuring they aren't needed, as they might have been left on standby from a previous phone system upgrade. Sometimes these units get left behind even if they aren’t currently powered on. Just be cautious—unplugging them might lead to unexpected issues if they are, in fact, still connected to anything vital.