Telephone handset amplifier circuit

Telephone handset detector

Telephone handset emulator

Telephone handset interface device

Telephone handset interface with feedback control

Telephone handset interface with feedback control

Telephone handset microphone level adjustment

Telephone handset with user-adjustable amplitude, default...

Telephone having a speech ban limiting function

Telephone having a speech band limiting function

Telephone having automatic gain control means

Telephone having four VAD circuits

Telephone having separate power circuit for supplying power to s

Telephone headset amplifier and method of operation

Telephone headset amplifier with battery saver, receive line noi

Telephone headset amplifier with battery saver, receive line noi

Telephone headset amplifier with noise blanking capability

Telephone headset in-use indicator

Telephone headset interface circuit

Telephone hold circuit