Westinghouse Security Systems

I have an old Westinghouse Security Systems that works internally fine, but it's developed a "short" on the telephone line as far as my Internet connection is concerned. I've since disconnected the device from my telephone line and discontinued my monitoring service, but the unit keeps alarming that the telephone connection is bad. The system works just fine as an internal, non-reporting alarm system -- How can I disarm the telephone reporting function of the device? I have the original Owners Manual, but it does not cover this.

AL