Data circuit-terminating equipment with power source device attached thereto

Claim 2

A data circuit-terminating equipment with a power source device attached thereto comprising: a data circuit-terminating equipment which is connect­ed to a telephone circuit and a data terminal equipment for demodulating a circuit signal which is input from said telephone circuit and supplying the demodulated signal to said data terminal equipment; and a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook when said circuit signals overlap with each other and supplying said power to said data circuit-­terminating equipment.

Claim 3

A data circuit-terminating equipment with a power source device attached thereto according to Claim 1, wherein said power source device includes a power converter circuit for converting said offhook current to said power.

Claim 4

A data circuit-terminating equipment with a power source device attached thereto according to Claim 2, wherein said power source device includes a battery for supplying a battery power to said data circuit-terminating equipment only at the time of onhook.

Claim 5

A data circuit-terminating equipment with a power source device attached thereto according to Claim 2, wherein said power converter circuit includes a DC-DC converter for converting said offhook current to a DC current having a different value.

Claim 6

A data circuit-terminating equipment with a power source device attached thereto according to Claim 4, wherein said DC-DC converter is a self-excited converter.

Claim 7

A data circuit-terminating equipment with a power source device attached thereto according to Claim 1, wherein said data circuit terminating equipment is a modem includ­ing: a modulation and demodulation circuit for modulating a signal supplied from said data terminal equipment and demodulating a circuit signal supplied from said telephone circuit; a net control unit for controlling the connection between said modulation and demodulation circuit and said telephone circuit; and a two-wire four-wire circuit connected to said modula­tion and demodulation circuit through said telephone circuit which is into a transmitting circuit and a receiving cir­cuit.

Claim 8

A data circuit-terminating equipment with a power source device attached thereto according to Claim 6, wherein said two-wire four-wire circuit includes: a light receiving element for receiving a signal in the form of light transmitted from said modulation and demodula­tion circuit; and a light emitting element for emitting a signal in the form of light to said modulation and demodulation circuit.

Claim 9

A data circuit-terminating equipment with a power source device attached thereto according to Claim 6, wherein said net control unit includes a light receiving element for detecting the offhook state.

Claim 10

A data circuit-terminating equipment with a power source device attached thereto according to Claim 6, wherein said net control unit includes a constant-current circuit for keeping said offhook current in the form of a constant current.

Claim 11

A data circuit-terminating equipment with a power source device attached thereto according to Claim 6, wherein said net control unit includes a shunt regulator for sup­pressing the excess of said offhook current output from said constant-current circuit in the form of a constant current.

Claim 12

A data circuit-terminating equipment with a power source device attached thereto according to Claim 6, wherein said net control unit includes a smoothing circuit for smoothing said offhook current output from said constant-current circuit in the form of a constant current.

Claim 13

A data circuit-terminating equipment with a power source device attached thereto according to Claim 10, wherein said net control unit includes a smoothing circuit for smoothing said offhook current output from said shunt regulator in the form of a constant current.

Claim 14

A data circuit-terminating equipment with a power source device attached thereto comprising: a data circuit-terminating equipment composed of: a modulation and demodulation circuit for modulating a signal supplied from a data terminal equipment and demodulating a circuit signal supplied from a telephone circuit; a net control unit for controlling the connection between said modulation and demodulation circuit and said telephone circuit; and a two-wire four-wire circuit connected to said modulation and demodulation circuit through said telephone circuit which is divided into a transmitting circuit and a receiving circuit; said net control unit including a first light receiving element for detecting the offhook state, a constant-current circuit for keeping an offhook current in the form of a constant current, a shunt regulator for suppressing the excess of said offhook current output from said constant-current circuit in the form of a constant current and a smoothing circuit for smoothing said offhook current output from said constant-current circuit in the form of a constant current and said two-wire four-wire circuit including a second light receiving element for receiving a signal in the form of light transmitted from said modulation and demodulation circuit, and a light emitting element for emitting a signal in the form of light to said modulation and demodulation circuit; said data circuit-terminating equipment being a modem which is connected to said telephone circuit and said data terminal equipment so as to demodulate said circuit signal input from said telephone circuit and output said signal to said data terminal equipment, and modulate a signal input from said data terminal equipment and supply said signal to said telephone circuit; and a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook when said circuit signals overlap with each other and supplying said power to said data circuit-terminating equipment.

Claim 15

A data circuit-terminating equipment with a power source device attached thereto comprising: a data circuit-terminating equipment composed of: a modulation and demodulation circuit for modulating a signal supplied from a data terminal equipment and demodulating a circuit signal supplied from a telephone circuit; a net control unit for controlling the connection between said modulation and demodulation circuit and said telephone circuit; and a two-wire four-wire circuit connected to said modulation and demodulation circuit through said telephone circuit which is divided into a transmitting circuit and a receiving circuit; said net control unit including a first light receiving element for detecting the offhook state, a constant-current circuit for keeping an offhook current in the form of a constant current, a shunt regulator for suppressing the excess of said offhook current output from said constant-current circuit in the form of a constant current and a smoothing circuit for smoothing said offhook current output from said constant-current circuit in the form of a constant current and said two-wire four-wire circuit including a second light receiving element for receiving a signal in the form of light transmitted from said modulation and demodulation circuit, and a light emitting element for emitting a signal in the form of light to said modulation and demodulation circuit; said data circuit-terminating equipment being a modem which is connected to said telephone circuit and said data terminal equipment so as to demodulate said circuit signal input from said telephone circuit and output said signal to said data terminal equipment, and modulate a signal input from said data terminal equipment and supply said signal to said telephone circuit; and a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook when said circuit signals overlap with each other and supplying said power to said data circuit-terminating equipment.

Claim 16

A data circuit-terminating equipment with a power source device attached thereto according to Claim 13, wherein said power source device includes a power converter circuit for converting said offhook current to said power.

Claim 17

A data circuit-terminating equipment with a power source device attached thereto according to Claim 14, wherein said power source device includes a battery for supplying a power to said data circuit-terminating equipment only at the time of onhook.

Claim 18

A data circuit-terminating equipment with a power source device attached thereto according to Claim 14, wherein said power source device includes a DC-DC converter for converting said offhook current to a DC current having a different value.

Claim 19

A data circuit-terminating equipment with a power source device attached thereto according to Claim 16, wherein said DC-DC converter is a self-excited converter.

Claim 20

A data circuit-terminating equipment with a power source device attached thereto according to Claim 16, wherein said DC-DC converter outputs two kinds of currents which are to be supplied to said modulation and demodulation circuit and said two-wire four-wire circuit, respectively.

Claim 21

A data circuit-terminating equipment with a power source device attached thereto according to Claim 17, wherein said power source device further includes a battery for supplying a power to said data circuit-terminating equipment only at the time of onhook, and said DC-DC converter outputs two kinds of currents which are to be supplied to said modulation and demodulation circuit and said two-wire four-wire circuit, respectively.