Last number redial device

Claim 2

A telephone last number redial device, comprising: a first register operable to selectably store a first, threshold portion (N) of a telephone number (N+M) produced during a telephone dialing sequence; a second register operable to alternately store said first, threshold portion (N) of said telephone number (N+M) produced during said telephone dialing sequence; a third register for storing a second, terminal portion (M) of said telephone number (N+M) produced during said telephone dialing sequence; select means for alternately coupling a selected one of said first register and said second register to said third register, for storing said first, threshold telephone number portion (N) during said telephone dialing sequence, and for accessing said first, threshold telephone number portion (N) during a last number redial sequence; and a counter, operable to produce a toggle signal in response to a threshold count (N+1) during said telephone dialing sequence, said threshold count being indicative of a valid phone number entry, said toggle signal being coupled to said select means whereby said selected one of said first register and said second register is coupled to said third register, such that said second, terminal portion (M) of said telephone number, when entered, is concatenated with said first, threshold portion (N) of said telephone number to store said telephone number (N+M) for access during said last number redial sequence.

Claim 3

The device of claim 1, said select means further comprising: a flip-flop coupled to said counter, said flip-flop being operable to alternately store a true (Q) signal and a complement (Q) signal in response to said toggle signal; gating means, coupled to said flip-flop to receive said true signal (Q) and said complement signal (Q), for alternately producing in response thereto a first register select signal and a second register select signal, whereby a threshold count (N+1) during a telephone dialing sequence alternately selects said first register and said second register; and second gating means for detecting said first register select signal, for detecting said second register select signal, and for coupling said third register to said selected one of said first register and second register in response thereto, whereby said first, threshold portion (N) of said telephone number is concatenated with said second, terminal portion (M) of said telephone number to store said telephone number (N+M) for access during said last number redial sequence.

Claim 4

The device of claim 2, further comprising: means for setting said first or second, and third registers to store said telephone number during said telephone number dialing sequence and for accessing a telephone number stored in said first or second, and third registers during said last number redial sequence.

Claim 5

The device of claim 3, further comprising: buffer means for coupling said first or second, and third registers to store said telephone number during a telephone number dialing sequence and for coupling said first or second, and third registers to access said telephone number during a last number redial sequence.

Claim 6

In a telephone set including a dialing circuit and a line output circuit, a last number redial device, comprising: a first register, capable of being coupled to selectively receive a first, threshold portion (N) of a telephone number (N+M) from the telephone set dialing circuit, produced during a telephone dialing sequence, and to selectively transmit said first, threshold portion of the telephone number to said telephone set output circuit, during a last number redial sequence; a second register, alternatively capable of being coupled to selectively receive said first, threshold portion of said telephone number from said telephone set dialing circuit during said telephone dialing sequence, and to selectively transmit said first, threshold portion of said telephone number to said telephone set line output circuit during said last number redial sequence; a third register, coupled to selectively receive a second, terminal portion (M) of said telephone number from said telephone set dialing circuit during said telephone dialing sequence and to transmit said second, terminal portion of said telephone number to said telephone set line output circuit during said last number redial sequence; a counter, coupled to said dialing circuit and operable to produce a toggle signal in response to a threshold count (N+1) during said telephone dialing sequence, said threshold count being indicative of a valid telephone number entry; a flip-flop, coupled to said counter to receive said toggle signal and operable to alternately produce a true (Q) signal output and a complement (Q) signal output in response thereto; and gating means, coupled to receive said true and complement signal outputs from said flip-flop and operable in response thereto to produce corresponding register select outputs, a first register select output coupling said first register to said third register, a second register select output coupling said second register to said third register, whereby said first, threshold portion of said telephone number is concatenated with said second, terminal portion of said telephone number.

Claim 7

In a telephone set including a dialing circuit and a line output circuit, a last number redial device, comprising: a first register, capable of being coupled to selectively receive a first, threshold portion (N) of a telephone number (N+M) from the telephone set dialing circuit, produced during a telephone dialing sequence, and to selectively transmit said first, threshold portion of the telephone number to said telephone set output circuit, during a last number redial sequence; a second register, alternatively capable of being coupled to selectively receive said first, threshold portion of said telephone number from said telephone set dialing circuit during said telephone dialing sequence, and to selectively transmit said first, threshold portion of said telephone number to said telephone set line output circuit during said last number redial sequence; a third register, coupled to selectively receive a second, terminal portion (M) of said telephone number from said telephone set dialing circuit during said telephone dialing sequence and to transmit said second, terminal portion of said telephone number to said telephone set line output circuit during said last number redial sequence; a counter, coupled to said dialing circuit and operable to produce a toggle signal in response to a threshold count (N+1) during said telephone dialing sequence, said threshold count being indicative of a valid telephone number entry; a flip-flop, coupled to said counter to receive said toggle signal and operable to alternately produce a true (Q) signal output and a complement (Q) signal output in response thereto; and gating means, coupled to receive said true and complement signal outputs from said flip-flop and operable in response thereto to produce corresponding register select outputs, a first register select output coupling said first register to said third register, a second register select output coupling said second register to said third register, whereby said first, threshold portion of said telephone number is concatenated with said second, terminal portion of said telephone number.

Claim 8

The device of claim 5, further comprising: second gating means, coupled to receive said first and second select signals and to select said third register in response thereto.

Claim 9

The device of claim 6, further comprising: means for operating said first, second, and third registers to receive said telephone number during said telephone dialing sequence and to transmit said telephone number during said last number redial sequence.

Claim 10

The device of claim 7, further comprising: buffer means for coupling first or second, and third registers to store said telephone number during said telephone number dialing sequence and for coupling said first or second, and third registers to access said telephone number during said last number redial sequence.

Claim 11

The device of claim 5, wherein said dialing circuit is a pulse dialing circuit.

Claim 12

The device of claim 5, wherein said dialing circuit is a dual tone multi-frequency (DTMF) dialing circuit.

Claim 13

The device of claim 5, said gating means further comprising: a first gate circuit, coupled to said flip-flop to receive said true signal (Q) and said complement signal (Q), for alternately producing in response thereto, said first register select signal and said second register select signal, whereby a threshold count (N+1) during a telephone dialing sequence, alternately selects said first register and said second register; and a second gate circuit for detecting said first register select signal, for detecting said second register select signal, and for coupling said third register to said selected one of said first register and said second register in response thereto, whereby said first, threshold portion of said telephone number is concatenated with said second, terminal portion of said telephone number to store said telephone number for access during said last number redial sequence.

Claim 18

A telephone last number redial device comprising: means for temporarily storing dialed digits for at least the duration of a telephone dialing sequence; a counter, operable to produce a toggle signal in response to a threshold count during a telephone dialing sequence, said count being indicative of a phone number entry; means, responsive to said toggle signal, for retaining said digits representing a telephone number after said dialing sequence; and means for accessing said telephone number during a last number redial sequence.

Claim 19

A telephone last number redial device comprising: means for temporarily storing dialed digits for at least the duration of a telephone dialing sequence; a counter, operable to produce a toggle signal in response to a threshold count during a telephone dialing sequence, said count being indicative of a phone number entry; means, responsive to said toggle signal, for retaining said digits representing a telephone number after said dialing sequence; and means for accessing said telephone number during a last number redial sequence.

Claim 20

The device of claim 14 wherein said temporary storing means comprises a selected first one of at least two registers and said retaining means comprises means for selecting another of said registers to receive digits during a next dialing sequence, thereby preserving the contents of said first register.

Claim 21

The device of claim 14 wherein said first register is operable to store a first threshold portion of a telephone number, and further comprising: a second register operable to alternately store said first, threshold portion of said telephone number; and a third register for storing a second terminal portion of said telephone number.