EXTENSION PHONE TRANSCEIVER SYSTEM USING A FREQUENCY OF 900MHZ FOR A TELEPHONE EXCHANGE, ESPECIALLY CONCERNED WITH MITIGATING THE INCONVENIENCE OF EXTENSION WIRING BY USING A RADIO FREQUENCY OF 900MHZ WITHOUT THE NECESSITY OF SPECIAL INTERNAL WIRING

摘要

PURPOSE: An extension phone transceiver system using a frequency of 900MHz is provided to expand a radius of phone usage and to reduce a burden of extension installation costs by using a radio frequency of 900MHz without the necessity of additional internal wiring and an expert's installation and maintenance. CONSTITUTION: The first modulation/demodulation part(6) modulates a voice signal delivered from an extension of a PBX(Private Branch eXchange). The first transmitting part(3) carries the modulated signal with a frequency of 900MHz. The second receiving part(2) receives the signal transmitted from the first transmitting part(3). The second modulation/demodulation part(6) demodulates the received signal, modulates it into a voice signal, and sends it to an extension phone. The second modulation/demodulation part(5) modulates a voice signal transferred from the extension phone. The second transmitting part(1) carries the modulated signal with a frequency of 900MHz. The first receiving part(4) receives the signal transmitted from the second transmitting part(1). The second modulation/demodulation part(6) demodulates the received signal into a voice signal and sends it to an extension terminal.