The Fiber Optic Link T1/E1 Model 2 (backwards compatible with the Model 1) System processes incoming bipolar signals (7.2 V P-P Max) within a bandwidth of 100 KHz to 10 MHz T-1 (1.544MbpS) or (CCITT 2.048MbpS), optically transmits these signals via fiber optic cable and converts the signal to the original electrical signal with minimal gain or loss.

Output to the copper line is automatically maintained at a nominal level. Transient voltages appearing on or between the 4-wire pairs and/or power supply input are limited by thermistors, gas tubes and MOVs.