The TSJ X6 A, TSJ X6 A 10/100 and TSJ 10/100 are high-speed, high-current solid state devices designed to protect equipment from transient over voltages on T1/E1 and 10/100 Base-T lines. They perform this function by utilizing silicon avalanche diodes to limit the magnitude of transient over voltages on the protected wire pairs. Continuous bi-polar, bi-directional, non-interrupting protection is provided. The TSJ X6 A is configured to protect six separate T1/E1 lines, the TSJ X6 10/100 is configured to protect six separate 10/100 Base-T Ethernet lines, and the TSJ 10/100 2 port is configured to protect two separate 10/100 Base-T Ethernet lines. In the unlikely event of failure, the protection module will disrupt the communication line, and the module can be replaced to aid in the system trouble shooting process. All of the protection modules connect to the service in a pass through configuration with a specific/preferred protected and in-coming cable orientation. The input and output connections for the T1/E1 model are female RJ-48C connectors, and are shielded RJ-45 Cat5 for the 10/100 Base-T model.