Wally,
Gotta break it down to the device (I think you are assuming).
First, can you plug in a phone to that line and it works OK with little noise. If you dial the number to your paging company, does the called end answer with a tone? If yes, then the line and far end paging company good.
Second, Does the Laser seize the line or you get nothing? Can you dial into a Laser 4000 (not sure, but you can dial into a M5)? If no, then it's the laser.
Maybe you did this, but you didn't provide any details.
Big