The 3B1S-300 & 3B1FS-240 premium series 5-pin solid-state protector modules are designed to provide superior transient and power fault protection for most standard telephone line applications. These solidstate modules are particularly suited to applications that require the protection of very sensitive digital equipment due to their nano-second reaction time. The balanced configuration of these modules provides the best protection against a line-to-line, metallic surge, where there is a large voltage differential between the two sides of the circuit. The characteristics of the solid-state protector are far superior to gas tube technology in speed of response and are virtually immune to overshoot, aging, and failure due to repeated tripping within rated limits. The 4B1** series features PTC (positive temperature coefficient) technology. These optional self-resetting current limiters provide effective protection from 'sneak current' faults. The PTC is vastly superior to the competition s heat coil solution, which requires that the module be replaced after each 'sneak current' event. Nanosecond response time. External failsafe mechanismthat permanently grounds the module under sustained high current conditions. Balanced operation. Integrated Test Points. UL & cUL listed, R.U.S. approved. Designed to meet or exceed Telcordia standards