Meridian 1 and Amplifier AM1120 for louspeaker notifications/alerts in the office

[beisa]

VERSION 2111
RELEASE 25
ISSUE 15 +
PSWV VERSION: PSWV 33

Greetings!
Can you please help me with one thing? We absolutely do not know what to do, since this setting was made before us.
Our meridian is connected to the amplifier (AM1000 MKII). Before, this used to loudspeaker announcements/alert to the entire office.
As far as we know, a some DN was dialed and then it was possible to speak. Or some key was introduced before that.
The problem is, nobody knows this number. Сan anyone know how to look at this DN on the meridian or what type usually is it? And in general where it can be configured.

I don't really have anyone else to turn to Thanks in advance!

*I attach screenshots

 

[bdk76]

It could either be a FXO (CO) port off of a Universal Trunk Card, or a FXS Port (Analog) off of an Analog Line Card.

My first guess would be an FSX Analog port, put an analog phone on the lone going in to the 'Tel Line" port on the Amp, and call a digital set with a display, it will probably show the name and extension of that analog port.