I am planing to not have my security system moniter so I did not hooked up telephone line to system.system show trouble # 3.how I can get rid of it.

Not sure if the location is 015 or 380, 1 of them is Communication Disable, the other is telephone Line Monitor, change the values of both with Installers code.

Section 015 turn off 7, then section 380 turn off 1