The 232B/E is a two-stage transient voltage protector the provides primary and secondary protection against lightning, inductive switching and electrostatic discharge (ESD) transient threats. The first stage diverts the transient current through the ground terminal return path and the second stage clamps the voltage to a safe level without interuption of service. The 232B/E is designed to protect two line pairs or four (4) data lines from common-mode (line-to-ground) lightning or switching transients. The datalines are isolated to prevent near or far end cross talk problems. This product can also be used on data and transmission lines, security, timing and control interface circuits.