MEASUREMENT & CONTROL Measurement and control devices are highly sensitive and exposed to overvoltages and they do therefore require fine protection for they can withstand a small level of residual voltage (level of protection) from upstream protectors. Terminal connector based protectors The BNV series of surge protective devices has been designed for protection of analog and digital signals against transient overvoltages. These devices do both provide common mode and differential mode protection along with built-in disconnection. SUB-D connector based protectors The DB series of surge protective devices has been designed for protection against transient overvoltages in communication systems. The aerial configuration of the series enables direct connection to the equipment that needs protection.