At present we have a Inter Tel 3000 with analog PSTN CO lines.
We are upgrading to TI in the near future, and my question is can I install the T1/PRI module and activate it without affecting the existing CO line scheme of the system, and if this is possible is there a way to test the operation of the module with a loop back or similar.
The service provider has already installed the T1 interface which is a Adtran Total Access 924e.
Any advice would be much appreciated, on both questions.

PS I am the quasi-telephone "Manager" at our company just because I was an Inside Plant Tech in the 1970's.