The Model 1830 Surge Protectors are designed for use on T1 and E1 lines entering Customer Premises and Wireless Transmission Facilities. The 1830 provides Secondary Protection as per UL497A. The principal use is for protection of telephone equipment against direct and induced lightning surges, power-line disturbances and ground potential rises. One Protector is used for the transmit pair and a second Protector is for the receive pair. Characteristics