Telephone call loudspeaker monitoring and relay control circuit

Claim 2

A relay operating circuit comprising a means for generating a first and second pulse of fixed duration, said second pulse occurring after at least a predetermined time delay; a first inverting circuit means selectively connected to the output of the pulse generating means for producing a first inverted output pulse in response to the first pulse of fixed duration from the pulse generating means; a second inverting circuit means connected to the output of the first inverting means for producing an output signal in response to the output pulse from the first inverter means, the second inverter means output having the same polarity as the first pulse at the input of the first inverting means; feedback means connected between the output of the second inverting means and the input of the first inverting means for holding the output of the second inverting means at the level to which it is set by the first inverted output pulse from the first inverting means after the termination of the output pulse from the first inverting circuit; means, connected to the second inverting means, responsive to the output of the second inverting means, for operating a relay; and relay contact means connected between the pulse generating means and the first and second inverting means, said contacts responsive to the operation of the relay for selectively disconnecting the input of the first inverting means from the output of the pulse genErating means and connecting the second pulse of fixed duration from the pulse generating means to the input of the second inverting means, said pulse resetting said second inverter means to produce an output signal releasing said relay, and thereby reconnecting the output of the pulse generating means to the first inverting circuit.

Claim 3

A relay operating circuit as in claim 1 in which the means for generating pulses of fixed duration comprises an inverter means operated in response to the closure of an input key contact.

Claim 4

A relay operating circuit as in claim 2, further comprising a second and third means for generating pulses of fixed duration in response to the opening of a second input key contact, said second and third means being connected in parallel as inputs to said second inverting means.

Claim 5

A relay operating circuit as in claim 1 wherein the inverting means and pulse generating means comprise MOS integrated circuits powered from a voltage source used to operate the relay and having an operating voltage conventional to telephone systems.

Claim 6

A relay operating circuit as in claim 3 wherein; a first means for generating a first and second pulse of fixed duration has an input connected to a non-locking key switch in a telephone set, and; the second and third pulse generating means have a common input connected to a contact on the hookswitch of a telephone set.

Claim 7

A relay operating circuit as in claim 1 wherein; the relay is used to connect and disconnect a loudspeaker and amplifier from a line circuit means of a telephone to thereby permit outgoing dialling through the loudspeaker while a handset remains on-hook.

Claim 8

A relay operating circuit as in claim 3 wherein the time duration of the output pulse of the three pulse generating means is determined by the time constants of R-C networks connected to the inputs of inverters and the time constants are less than the operate and release time of the relay.

Claim 9

In a telephone system having a line circuit means and at least one telephone set with a loudspeaker and amplifier means, means for connecting the telephone set to the line circuit means comprising; a non-locking key contact and a hookswitch contact connected between the telephone set and the line circuit means means responsive to successive operations of the non-locking key contact for alternately operating and releasing a relay to connect and disconnect the loudspeaker and amplifier from the line circuit means of the telephone system thereby permitting outgoing dialling and monitoring of calls from the telephone set without removing a handset and releasing the hookswitch; and means responsive to the operation of the hookswitch contact for releasing the relay to disconnect the loudspeaker and amplifier from the line circuit means of said telephone system.

Claim 10

In a telephone system having a line circuit means and at least one telephone set with a loudspeaker and amplifier means, means for connecting the telephone set to the line circuit means comprising; a non-locking key contact and a hookswitch contact connected between the telephone set and the line circuit means means responsive to successive operations of the non-locking key contact for alternately operating and releasing a relay to connect and disconnect the loudspeaker and amplifier from the line circuit means of the telephone system thereby permitting outgoing dialling and monitoring of calls from the telephone set without removing a handset and releasing the hookswitch; and means responsive to the operation of the hookswitch contact for releasing the relay to disconnect the loudspeaker and amplifier from the line circuit means of said telephone system.

Claim 11

In a telephone system as in claim 8 wherein the means responsive to the successive operations of the non-locking key contact comprises a means responsive to the successive operations of the non-locking key contact for generating a first and second pulse of fixed duration, said second pulse occurring after at least a predetermined time delay; a first inverting circuit means selectively connected to the output of the pulse generating means for producing a first inverted output pulse in response to the first pulse of fixed duration from the pulse generating means; a second inverting circuit means connected to the output of the first inverting means for producing an output signal in response to the output pulse from the first inverter means, the second inverter means output having the same polarity as the first pulse of fixed duration to the first inverting means; feedback means connected between the output of the second inverting means and the input of the first inverting means for holding the output of the second inverting means at the level to which it is set by the first inverted output pulse from the first inverting meaNs after the termination of the output pulse from the first inverting circuit; means, connected to the second inverting means, responsive to the output of the second inverting means, for operating a relay; and relay contact means responsive to the operation of the relay for selectively disconnecting the input of the first inverting means from the output of the pulse generating means and connecting the second pulse of fixed duration from the pulse generating means to the input of the second inverting means, said pulse resetting said second inverter means to produce an output signal releasing said relay, and thereby reconnecting the output of the pulse generating means to the first inverting circuit.