FYI,
I am not a telecom tech but I have dealt with communication issues with security and building controls such as fire and HVAC..
All I can say is baud and parity and bits make a difference as well as the correct cable to connect with.

Assuming the front end will work to connect with.

Of course the last obstacle is, did someone change the default password?

I had some motorola paging terminals once that required hayes1200 baud modems ( non auto baud) to work.
They would not work with autobaud modems.
Try to find one even 10 years ago,

There is no such thing as stupid questions.
Just stupid answers.