Improved page party system

A page party communication system having a plurality of stations joined by a page line and by a single party line for providing plural full duplex voice conferencing channels on the single party line, each station comprising:

• a current source line driver selectively coupled to either the page line for transmitting a paging message or to the party line for transmitting outgoing or receiving incoming voice signals between stations;
• a channel selector switch for selecting one of said conferencing channels, each of said conferencing channels having a unique frequency band corresponding thereto;
• audio input means for receiving outgoing voice signals;
• a voice modem, responsive to said audio input means, including
• (a) means for amplitude modulating a carrier with said outgoing voice signal and for suppressing the carrier and one its sidebands to produce a single sideband suppressed carrier spectrum;
• (b) means for translating that spectrum to the frequency band of the selected conferencing channel;
• (c) means, responsive to said line driver, for receiving single sideband suppressed carrier spectra representing incoming voice signals from other stations on the party line and for translating incoming spectra located at the frequency of the selected channel to baseband;
• and
• (d) means for suppressing sidetone from incoming voice signals to produce a suppressed sidetone output signal;
• and
• means, coupled to the voice modem, for generating an audio output in response to said suppressed sidetone output signal.