How do I get telephone equipment numbers

[patrick]

We use an ericsson system for our phone extensions at work. Basically every port has a hard wired equipment number which you can put an extension on.

Now when I took over the job here a bunch of ports were unmarked. They are functional but I can't tell what the equipment numbers are. Is there some software I can use to pick them up by plugging in a laptop, or maybe some hardware tool I can get?

I've left messages with our contact at Didata who originally wired us, but they never get back to us.