Interface for isdn channels

Claim 2

An interface for ISDN channels, comprising: means for converting an analog signal from an analog communication line connected to an analog communication terminal into digital data and sending the digital data to a B-channel of ISDN; means for converting digital data from the B-channel of ISDN into an analog signal and sending the analog signal to said analog communication line; means for detecting a DC loop on the analog communication line; means for receiving a dial signal from the analog communication terminal; and means for controlling connection to the B-channel of ISDN in response to both formation of the DC loop on the analog communication line and the dial signal from the analog communication terminal and for controlling release of the B-channel of ISDN in response to release of the DC loop on the analog communication line.

Claim 3

An interface according to claim 1 wherein said control means is for receiving call information from said analog communication terminal and controlling line connection in accordance with the received call information.

Claim 4

An interface according to claim 2 wherein said detecting means detects a status of said analog communication terminal, and wherein said control means controls the line connection when a start status of said analog communication terminal indicated by the DC loop is detected by said detecting means.

Claim 5

An interface according to claim 1, further comprising means for sending a tone signal to said analog communication terminal wherein said analog communication terminal is informed of ISDN line connection status by the tone signal of the tone signal sending means.

Claim 6

An interface according to claim 1 further comprising means for sending a call signal to said analog communication terminal in response to detection of a call from the ISDN channels.

Claim 7

An interface for ISDN channels, comprising; a first terminal for connecting to an analog communication line; a second terminal for connecting to ISDN channels; A/D convertor means for converting an analog signal from the analog communication line into digital data and sending the digital data to a B-channel of ISDN; D/A convertor means for converting digital data from the B-channel of ISDN into an analog signal and sending the analog signal to the analog communication line; means for detecting a DC loop on the analog communication line; means for receiving a dial signal from the analog communication line; and means for controlling connection to the B-channel of ISDN in response to both formation of a DC loop on the analog communication line and the dial signal from the analog communication line and for controlling release from the B-channel of ISDN in response to release of the DC loop on the analog communication line.

Claim 8

An interface for ISDN channels, comprising; a first terminal for connecting to an analog communication line; a second terminal for connecting to ISDN channels; A/D convertor means for converting an analog signal from the analog communication line into digital data and sending the digital data to a B-channel of ISDN; D/A convertor means for converting digital data from the B-channel of ISDN into an analog signal and sending the analog signal to the analog communication line; means for detecting a DC loop on the analog communication line; means for receiving a dial signal from the analog communication line; and means for controlling connection to the B-channel of ISDN in response to both formation of a DC loop on the analog communication line and the dial signal from the analog communication line and for controlling release from the B-channel of ISDN in response to release of the DC loop on the analog communication line.

Claim 9

An interface according to claim 6 wherein: said receiving means detects call information from the analog communication line connected to said first terminal; and said controlling means controls connection of the digital line connected to said second terminal in accordance with the detection by said detecting means and said receiving means.

Claim 10

An interface according to claim 7, further comprising a tone signal generation circuit which generates a tone signal representing a status of ISDN line connection control by said control circuit and sending the tone signal to the analog communication line.

Claim 11

An interface according to claim 6, further comprising a call signal generating circuit for generating a call signal and sending the call signal to the analog communication line, wherein said call signal generating circuit generates the call signal in response to a communication request from ISDN.

Claim 12

An interface connected between an analog communication line and ISDN channels, comprising; means for converting an analog signal from the analog communication line into digital data and sending the digital data to a B-channel of ISDN; means for converting digital data from the B-channel of ISDN into an analog signal and sending the analog signal to the analog communication line; first detection means for detecting a loop on the analog communication line; second detection means for detecting call information from the analog communication line; means for generating a call signal and sending the call signal to the analog communication line; and means for controlling connection to the B-channel of ISDN in response to both formation of the loop on the analog communication line and the call information, and for controlling release from the B-channel of ISDN in response to release of the loop on the analog communication line.

Claim 13

An interface connected between an analog communication line and ISDN channels, comprising; means for converting an analog signal from the analog communication line into digital data and sending the digital data to a B-channel of ISDN; means for converting digital data from the B-channel of ISDN into an analog signal and sending the analog signal to the analog communication line; first detection means for detecting a loop on the analog communication line; second detection means for detecting call information from the analog communication line; means for generating a call signal and sending the call signal to the analog communication line; and means for controlling connection to the B-channel of ISDN in response to both formation of the loop on the analog communication line and the call information, and for controlling release from the B-channel of ISDN in response to release of the loop on the analog communication line.

Claim 14

An interface according to claim 10 further comprising means for generating a tone signal representing a status of line connection control by said control means and sending the tone signal to the analog line.

Claim 15

An interface according to claim 2, 3 7 or 10 wherein said call information is dial information.

Claim 16

An interface according to claim 4, 8 or 11 wherein said tone signal sending means sends said tone signal indicating the line connection when the line connection control is completed.