Key telephone systems using pushbutton or rotary dials

Claim 2

A key telephone system for use with telephone sets having either pushbutton or rotary dials comprising two electronic digital signal receivers, one receiver being for pushbutton multifrequency dial signals, the other receiver being for rotary DC dial signals, common electronic control means for applying ringing current and lamp signal current to a called telephone station identified by said dial signals, means for giving answer supervision responsive to the detection of an answer at said called station, and means responsive to said answer supervision for removing said ringing and lamp currents from said station.

Claim 3

The telephone station of claim 1 and a plurality of relays for storing the digital value of said dial signals in binary form, a pair of relay contact trees operated by said relays for selectively extending a connection from sources of said ringing and lamp currents to a line designated by said dial signals.

Claim 4

The system of claim 1 and means associated with said current removal means for feeding back a latching signal to preclude any reapplication of said ringing current to said line until after the last party has released the connection.

Claim 5

A miniature key telephone system comprising a plurality of subscriber stations connected to a central office via some lines and connected to each other via at least one other line, a plurality of keys at each of said telephone stations for selecting between said lines, a multifrequency dial tone detector connected to said other line, means for re-encoding an M-out-of-N coded combination of said frequencies into a binary code, a plurality of binary weighted relays, means responsive to said re-encoded binary code for selectively operating said relays to store a dialled digit, and means comprising a pair of contact trees controlled by said relays for selectively applying at least one signal current to a called one of said stations.

Claim 6

A miniature key telephone system comprising a plurality of subscriber stations connected to a central office via some lines and connected to each other via at least one other line, a plurality of keys at each of said telephone stations for selecting between said lines, a multifrequency dial tone detector connected to said other line, means for re-encoding an M-out-of-N coded combination of said frequencies into a binary code, a plurality of binary weighted relays, means responsive to said re-encoded binary code for selectively operating said relays to store a dialled digit, and means comprising a pair of contact trees controlled by said relays for selectively applying at least one signal current to a called one of said stations.

Claim 7

The system of claim 4 and an electronic dial pulse detector means connected between said other line and said plurality of relays, means responsive to said dial pulse detector for storing a dialled digit by a selective operation of said plurality of relays.

Claim 8

The system of claim 5 wherein said dial pulse detector means comprises a control circuit and a plurality of electronic binary weighted channels, each of said electronic channels being individually associated with a corresponding one of said binary weighted relays, means responsive to each incoming dial pulse for operating at least one of said relays via said electronic channels, and means responsive to each relay operation for advancing a binary count of said relays by selectively activating said binary channels.

Claim 9

A electronic register circuit for DC dial pulse comprising a common control and a plurality of binary weighted electronic channels, a plurality of relays, each of said relays individually associated with one of said weighted channels, each of said relays having a single winding with said winding connected to the output of the associated channel and a first of its contacts connected to the input of the channel, said relay contacts being wired together in a binary coded combination, said common control comprising means for applying a dial pulse signal to said first of said contacts responsive to the receipt of each dial pulse, and means responsive to each pulse of said applied signal for operating at least one of said relays selected by the operated or unoperated conditions of said contacts, said contacts advancing the count in a binary code combination responsive to each incoming dial pulse.

Claim 10

A electronic register circuit for DC dial pulse comprising a common control and a plurality of binary weighted electronic channels, a plurality of relays, each of said relays individually associated with one of said weighted channels, each of said relays having a single winding with said winding connected to the output of the associated channel and a first of its contacts connected to the input of the channel, said relay contacts being wired together in a binary coded combination, said common control comprising means for applying a dial pulse signal to said first of said contacts responsive to the receipt of each dial pulse, and means responsive to each pulse of said applied signal for operating at least one of said relays selected by the operated or unoperated conditions of said contacts, said contacts advancing the count in a binary code combination responsive to each incoming dial pulse.

Claim 11

The register of claim 7 and an electronic switch means in each of said weighted channels for operating the relay individually associated therewith and means responsive to the operation of each of said electronic switch means for feeding back a latching current to hold said switch means and relay operated.

Claim 12

The register of claim 8 and means for selectively shunting the latched electronic switch means responsive to the operated combination of the combination of the latched switch means and operated contact of the relay for the same channel.

Claim 13

The register of claim 9 and means for shunting all of said electronic switch means responsive to dial signals other than said DC dial pulses.