Telephone line interface circuit
Telephone line interface circuit
Telephone line interface circuit and method
Telephone line interface circuit with voltage control
Telephone line interface circuit with voltage switching
Telephone line interface circuit without hookswitch relay
Telephone line interface with AC and DC transconductance loops
Telephone line overvoltage protection apparatus
Telephone line power utility circuit
Telephone line sourced power supply
Telephone line unit having programmable read-only memory
Telephone line-powered power supply for ancillary equipment...
Telephone loop monitoring and isolation system
Telephone loop-current regulator
Telephone network enclosure containing protected termination dev
Telephone network interface
Telephone network interface apparatus
Telephone network interface apparatus
Telephone network interface apparatus
Telephone network interface apparatus