Simultaneous protection of single-phase power supply and phone line

Telecommunication equipment which are connected to the power supply and the phone line such as answering machines, fax machines, and PCs with modem can receive the impact of surge voltages from their two inputs, which are the power supply and the phone connection. For such equipment two protectors are used in order to assure the complete protection.

For devices which are connected to the phone line and the power supply, combined protectors have been desigend which incorporate both the protection for a single-phase power supply with loads up to 10 A and the protection of one or two phone lines such as BTN or ISDN.