T1/E1 standard transient voltage suppressor. Each pair (pin 1 & 2 and pins 4 & 5) has 15 joules of SAD protection. In addition, each line has a parallel gas tube. Clamping voltage begins at 10 Volts. Connections may also be hard- wired. Each unit supplied with RJ48C (non-keyed) interface cable and ground conductor. Also accepts RJ11 plugs.