My Norstar M7208 phone wont ring. We've moved into a new facility and the ringer does not work now.

There is a chance if you reduce the volume.

If you have lines appearing on your phone and they don't ring you need to program lines to ring. This type of programming is done from a M7310 phone. Page 323 of this manual shows how to program this on a NorthStar MICS Ver 6 phone system.
http://pdf.textfiles.com/manuals/TELECOM-F-R/Nortel%20MICS%20System%20Installer%20Guide%206.1.pdf

Enter the programming mode : Feature **266344
Password:266344
You will have 4 programming buttons on your phone, normally the 2 top left and 2 top right of the 2 vertical rows.
top left = move up one level
lower left = back
top right = select
lower right = next
once you enter the programming mode press next to "Terminals and Sets"
press select
enter your extension number
press select
press next to "Line Access"
press select
press next to "Line Assignment"
press select
use the next key to go to the line you want and use the soft-key below the display to change it from "Appear" to "Appear and Ring"

There is a contact closure output on the common equipment ("KSU") which can activate an external signal on a ringing line.

This is tech side of programming and not Admin, if you don't know config password or how to program then call a tech.
If you do know then:
First find out what line #, do F*0 then press the button and note the full number on the display.
i.e. Line 5 in programming is Line 005, 025 or 031 depending on software version.

Sets/LineAccess/LineAssignment/Show line ***/Change to Appear Only or Not Assigned.

Does it ring when you move it to a known ringing port? Is it programmed to ring (Terminals & Sets) Appear and Ring? Do you have Automatic Set Relocation turned on so the extension number stays with the phone?

There are a lot of features to check for ringing, including the volume of the set.

Carl

Dial "F * 0" (Feature, star, zero), which is Button Inquiry, and press an intercom button to see the extension number of the telephone. If Set Relocation is set to "Yes", then the extension number & mailbox will follow the phone when it is moved. Move only two phones at a time, and wait until they completely "boot-up" before moving additional phones.
Hope this helps.

No, the M7208 is a propriatary set which requires the PBX to function, whereas the aastra phone is a stand alone set which requires a standard telephone line and a power source.

Featue *80 and then press volume bar to increase the volume of ur phone

My BT Meridian compact does not ring after it powered down in a thunder storm. The lines flash and can be answered as normal just no ringing sound

It's RINGING now! I followed the Set Programming instruction in our manual. It's in Configuration 3-21. It's a very old old Operator guide.
I am trying to find it online. In the mean time you can use the M7208 Phone Adminitration Overlay over the keys and program your phone by pressing Feature **266344
Here is a link to the overlay
Good Luck.