Line circuit for multiple line telephone

Claim 1

A plurality of line circuits in a multiple line telephone having a line switch for each line, and a hold switch for all lines, each of said line circuits connected to a telephone switching system via an associated line, said telephone switching system operated to apply alternating current ringing signal and loop current to a selected one of said lines, each of said line circuits comprising: a loop holding circuit connected to an associated line and said hold switch; a switching circuit connected to said holding circuit; and visual indicating means connected to said switching circuit; one of said line switches for each line operated to connect said visual indicating means to said line; whereby said loop current flows through said line switch and said visual indicating means; said visual indicating means operated in response to said loop current to generate a steady visual signal; said hold switch operated to generate a holding circuit enable signal and further generated to release said operated line switch; said holding circuit operated in response to said enable signal to conduct said loop current to said switching circuit; said switching circuit operated in response to said loop current to periodically, alternately apply and shunt, said loop current to and from said visual indicating means; said visual indicating means operated in response to said periodically applied loop current to generate a periodic visual signal of a first characteristic.