Adaptive multitone signaling method
Amplifier with double rail output
Apparatus and method for determining the source of a telephone c
Bell signal generating circuit
Call progress capability for a switched channel data service uni
Call progress capability for a switched channel data service uni
Call progress capability for a switched channel data service uni
Call progress tone generation in a communication system
Call progress tone generation in a communication system
Call progress tone generation in a communication system
Call signal generating circuit
Calling signal transmission apparatus
Control server employment of offer message from resource...
DC level trip detector
Detection of ground or loop start configuration in telephone loo
Digital tone detector
Electrical power and telephone ringer signal distribution system
Exchange apparatus enclosing a plurality of extension terminals
Generating a distinctive ring tone for a calling party subscribe
High bandwidth communication network and method