| 摘要 |
A portable telephone or other signaling system features a remote or portable unit responsive to operator voice and control signals to modulate infrared emitting diodes with narrowband, FM low duty cycle pulses which are received by a telephone network unit operative to demodulate the infrared signals, control the telephone network connection and to transmit and receive voice signals from the network. The portable unit utilizes narrowband FM pulse modulation to optimize the use of battery power. The portable unit further includes means for transmitting on-and-off hook indicia and dialing pulses with the same efficient, narrowband FM pulse modulation. The network base unit includes infrared receiving and decoding means in order to identify audio signals and apply them to the telephone network as well as to detect dial pulses and on- and off-hook indicia to process them for connecting and disconnecting the network unit to the telephone network. Audio signals from the telephone network are sent via a loudspeaker in the network unit to the region of the remote unit along with ring signals.
|
