Touch calling radio telephone terminal

Claim 1

A communication system comprising: a plurality of mobile radio units each equipped with a receiver, a transmitter and pushbutton operated tone generating means connected to said mobile unit transmitter, said mobile unit transmitter operated in response to manual operation of said tone generating means to transmit tone signals; a base station radio transmitter; a base station radio receiver; said base station receiver normally operated in response to receipt of voice signals from one of said mobile units to operate said base station transmitter to transmit said received voice signals to other ones of said mobile units; a plurality of individually numbered dial equipped telephone substations; automatic switching equipment, operable to establish circuit paths to selected ones of said substations in response to dial generated pulses; a tone signal converter, operable in response to receipt of tone signals corresponding to a substation number to convert said signals to pulses; and interface means connected between said switching equipment and said base station receiver, and including circuit connections to said tone signal converter, said interface means operated in response to receipt by said base station receiver of a first tone signal transmitted by one of said mobile units to complete a circuit connection from said interface means to said base station transmitter, and connect said tone signal converter to said switching equipment, and to operate said base station transmitter over said completed circuit connection between said interface means and said base station transmitter, to transmit a supervisory tone to said mobile radio units, signaling said mobile radio unit that transmitted said first tone signal, to transmit a plurality of second tones corresponding to a selected substation number; said tone signal converter operated in response to receipt by said base station receiver of said plurality of second tones transmitted by said mobile unit, to transmit a plurality of corresponding pulses to said switching equipment; said switching equipment operated in response to said pulses to establish a circuit path to said selected substation; and said interface means further operated to connect said base station receiver and said base station transmitter to said established circuit path.