Dial in Access

I need to figure out how to dial into my system and then be able to to call an extension?
I have several extensions set as door signals and need to call in to activate those at times.
I also want to call in and access my paging system.

I cannot find out which codes and /or set up i need to create to do this.
Thanks in advance.

DISA

Direct Inward System Access

BF

Got it. And it works.
Just didn’t know what to cal it. Thanks.