Nonlocking key telephone set

Claim 2

A key telephone set having a plurality of illuminatable nonlocking keys for selectively connecting the set to any of a plurality of telephone lines comprising means operative when said set is in the on-hook state for completing a path to supply illumination power to said keys in accordance with the respective supervisory state of each of said lines, and means operative when one of said keys has been operated and said set is in the off-hook state for disconnecting said illumination power from the remaining ones of said keys.

Claim 3

A key telephone set in accordance with claim 1 wherein said means for disconnecting includes means for supplying local power illumination to said one of said keys.

Claim 4

A key telephone set in accordance with claim 1 further comprising key control means operable when said set is in the off-hook condition for disabling said means for disconnecting and for reconnecting said illumination power to said keys for the illumination thereof in accordance with the respective supervisory states of said lines.

Claim 5

A key telephone set in accordance with claim 3 wherein said telephone set includes a HOLD button, and wherein said disabling means includes relay contact means controlled by said HOLD button.

Claim 6

In a key telephone system including a telephone set having a plurality of signaling lamps and a plurality of nonlocking keys for selectively connecting telephone lines to a terminating network said system further including at least one set of relay contacts responsive to said nonlocking keys for connecting said telephone lines to said network, a second set of relay contacts, for providing illumination power while in a first state of operation to said lamps for displaying full line status information when said telephone set is on-hook and for providing illumination power while in a second state of operation only to the one of said lamps corresponding to the line in use at said telephone set when said set is off-hook and, means operative to restore said second set of relay contacts to the first state of operation when said set is off-hook for displaying full line status information.

Claim 7

In a key telephone system including a telephone set having a plurality of signaling lamps and a plurality of nonlocking keys for selectively connecting telephone lines to a terminating network said system further including at least one set of relay contacts responsive to said nonlocking keys for connecting said telephone lines to said network, a second set of relay contacts, for providing illumination power while in a first state of operation to said lamps for displaying full line status information when said telephone set is on-hook and for providing illumination power while in a second state of operation only to the one of said lamps corresponding to the line in use at said telephone set when said set is off-hook and, means operative to restore said second set of relay contacts to the first state of operation when said set is off-hook for displaying full line status information.

Claim 8

Apparatus as in claim 5 wherein said means operative to restore said second set of relay contacts includes one of said nonlocking buttons on said key telephone set and a relay responsive to said one of said nonlocking buttons.

Claim 9

Apparatus as in claim 6 wherein said means operative to restore further includes a series connection between a source of potential and ground said series connection comprising the coil for operating said second set of relay contacts, the parallel connection of make contacts which are respectively operated with each of said first set of relay contacts, said coil being connected between said source of potential and said parallel connection of make contacts and parallel connected paths between said parallel connection of make contacts and ground including in the first path, the make contact of the relay responsive to said switchhook and the break contact of said relay responsive to said one of said nonlocking buttons and in the second path, the break contact of the relay responsive to said switchhook and the make contact of said relay responsive to said particular one of said nonlocking buttons.

Claim 10

Apparatus as in claim 7 wherein a selected one of said nonlocking keys operates at least one holding relay, and wherein the front contacts of said holding relay selectively interrupt the continuity of a particular set of said lines and ground.