Solenoid circuit for pushbutton release in telephones
AssigneeNorthern Electric Company Limited
InventorsGraham Stirling Laing, Shiro Tom Ito
Life of this patent
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Abstract
In a telephone unit having a plurality of line selection pushbuttons, normally released on replacement of the handset, an additional release switch is provided with associated circuitry, whereby when a speaker unit or "hands free" unit is attached, pushbuttons can be actuated by a solenoid, even though the handset is not removed. The normal hold button is altered to a momentary button, and the solenoid releases all depressed pushbuttons. An additional circuit is provided for preventing actuation of the solenoid and release of an actuated pushbutton on cessation of a call when an answering service module is connected.
Claims5
A pushbutton release circuit for a pushbutton telephone, comprising:
- a plurality of pushbuttons in a key strip and including a common button release latch bar;
- a first relay actuated by said pushbuttons;
- a hold button;
- a pushbutton release solenoid connected to said latch bar for actuation to release any depressed button;
- a second relay for actuating said solenoid;
- and for connection and disconnection of tip and ring lines in said telephone;
- a delay circuit for delaying actuation of said second relay until after actuation of said first relay;
- means actuated by said hold button to connect said delay circuit into the release circuit;
- actuation of said hold button connecting said delay circuit and releasing said first relay, the delay circuit energizing said second relay to actuate said solenoid after release of said first relay.
Dependencies are inferred from the claim text.