JPS63286050A - Isdn terminal adaptor - Google Patents

Abstract

PURPOSE:To attain the connection to an integral service digital network (ISDN) without modifying by superimposing a DC to a connection section with the G3 facsimile, detecting the hookup state of the G3 facsimile equipment, receiving a sent dial pulse or a DIMF signal and converting the result into the calling procedure to the ISDN. CONSTITUTION:When the G3 facsimile 3 equipment acquires a line, a DC loop is formed between the G3 facsimile equipment and a terminal adaptor. A DC loop detection circuit 10 of the terminal adaptor sends a loop detection signal to an ISDN communication control circuit 17. On the other hand, after the line acquisition, the G3 terminal equipment applies dialing to send a dial pulse or a DTMF signal. A dial signal discrimination circuit 14 of the terminal adaptor discriminates it and informs the dial signal to the ISDN communication control circuit 17. Thus, the channel B of the ISDN is set and the end-to-end communication is attained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an ISDN terminal adapter.

[Prior Art] A method for connecting a terminal device having a conventional interface to an l5DN (service integrated digital network) is described by CCITT.
1.480 series recommendations. This connection form is shown in Fig. 5. The conventional example shown in Fig. 5 connects the network termination equipment glNT that terminates subscriber lines and in-house buses, and the existing interface to I.
It has a terminal adapter 1 for converting to an SDN user network interface, and a terminal device TE2 having an existing V series or X series interface. Also,
The point connecting the terminal device TE2 and the terminal adapter l is called the R reference point, and the point connecting the terminal adapter l and the network termination device NT is called the T reference point.

The terminal adapter 1 has a function of converting a protocol for the terminal bag glTE2 into a protocol for one terminal device fiNT, a function of converting a protocol for the network terminal device NT into a protocol for the terminal device 1TE2, and a function of converting a protocol for the network terminal device NT into a protocol for the terminal device 1TE2.
It has a function of performing rate adaptation (speed matching) between the point and the T point.

[Problems to be solved by the invention] In the above conventional device, the existing 03 facsimile is
Since it has an interface to connect to the STN (Public Telephone Network), it is not subject to the above-mentioned 1.480 series recommendations, and there is a problem that it cannot be connected to ISDN as it is.

[Means for Solving the Problems] The present invention provides means for detecting the hook-up state of the G3 facsimile by superimposing a direct current on the connection part with the G3 facsimile, and detecting the dial pulse or DTMF signal sent from the G3 facsimile. an A/D conversion means for converting the procedure signal and image signal from the G3 facsimile into digital signals; means for notifying the G3 facsimile of the incoming call when there is an incoming call from the ISDN, and a G3 facsimile procedure signal and image signal received from the ISDN via the B channel. and D/A conversion means for converting the signal into an analog signal.

[Function] The present invention includes means for detecting the hook-up state of the G3 facsimile by superimposing a direct current on the connection part with the G3 facsimile, and a means for receiving the dial pulse or DTMF signal sent from the G3 facsimile and transmitting it to the ISDN. and a means for converting it into a calling procedure.

A/D conversion means for converting the procedure signal and image signal from the G3 facsimile into digital signals; and means for transmitting the digital signal via the B channel of ISDN;
means for notifying the G3 facsimile of the incoming call when there is an incoming call from the ISDN;
A D/D converter that converts the G3 facsimile procedure signal and image signal received from N via the B channel into analog signals.
Since the G3 facsimile is equipped with A conversion means, it is possible to connect to ISDN and perform mutual communication without modifying the G3 facsimile.

[Example] FIG. 1 is a configuration diagram showing an example of the present invention, and
2 is a diagram showing a state in which a facsimile machine is connected to a network termination equipment fiNT via a terminal adapter 2. FIG.

The G3 facsimile 3 is connected to a terminal adapter 2 via a line connection terminal, the terminal adapter 2 is connected to a network termination device NT at a reference point S, and the network termination device NT is connected to an l5DN (service integrated digital network). has been done.

FIG. 2 is a block diagram showing an example of the terminal adapter 2 shown in FIG. 1.

This terminal adapter 2 includes a DC loop detection circuit lO that detects a DC loop and outputs a loop detection signal.
and a DC superimposition circuit 1 that superimposes DC on the Ll and L22 terminals.
1, a hybrid transformer 12, a 16Hz generation circuit 13 that generates a 16Hz telephone ringing signal, and an L
It has a dial signal identification circuit 14 that identifies the dial signal input from the L and L2 terminals and outputs the dial signal.

The terminal adapter 2 also performs D/A conversion on the B channel data received from the ISDN, and converts the output signal of the hybrid transformer 12 into a D/A converter 15 and the output signal of the hybrid transformer 12. jI SDN that performs communication between the A/D conversion circuit 16 and the I SDN
It has a communication control circuit 17.

The loop detection signal is the output of the DC loop detection circuit 10, the 16Hz transmission command signal is the output of the ISDN communication control circuit 17, and the dial signal is the dial signal identified by the dial signal identification circuit 14. be.

A G3 facsimile 3 is connected to terminals L1 and L2 via metallic cables, and a network termination device NT is connected to terminals R and T via metallic cables.

The DC superimposition circuit 11 has terminals L1. G3 via L2
Apply connection voltage to the line connection terminal of facsimile 3.

A DC loop is formed by the line capture operation of the G3 facsimile 3. The DC loop detection circuit 10 detects this DC loop and notifies the ISDN communication control circuit 17 of the detected DC loop. The I5DN communication control circuit 17 thereby performs a startup procedure for the network, and the dial signal input to the LL and L2 terminals by the dialing operation of the G3 facsimile 3 is recognized by the dial signal identification circuit 14 as a dial number: I SDN communication control circuit 1
7 will be notified.

When there is an incoming call from the I SDN, the I SDN communication control circuit 17 outputs a 16 Hz transmission command signal to the G3 facsimile 3 via the LL and L2 terminals.
A generating circuit 13 sends out a 16 Hz signal.

Next, the signal operation at the time of receiving a call in the above embodiment will be explained.

FIG. 3 is a flowchart of signals when the terminal adapter 2 makes a call.

First, when the G3 facsimile 3 acquires a line, a DC loop is formed between the G3 facsimile 3 and the terminal adapter 2. The DC loop detection circuit lO of the terminal adapter 2 sends a loop detection signal to the l5DN communication control circuit 17. Upon receiving this, the 15DN communication control circuit 17 executes a network activation procedure and a link control procedure for the ISDN.

On the other hand, after acquiring the line, the G3 facsimile 3 performs a dialing operation and sends out a dial pulse or DTMF signal. The dial signal identification circuit 14 of the terminal adapter 2 identifies this and notifies the ISDN communication control circuit 17 of the dial signal. Upon receiving this, the ISDN communication control circuit 17 executes a connection procedure for the ISDN and establishes a communication path with the communication partner. Through the above operations, the B channel of the I5DN is turned on, and end-to-end communication becomes possible.

As a result, the CCI from the communication partner's 03 facsimile 3
TTT, 30 procedure signals NSF, C3I, DIS are received by the ISDN communication control circuit 17 via the B channel, converted to analog signals by the D/A converter 15, and sent to the hybrid transformer 12, terminal Ll, L2
is input to the G3 facsimile 3 via .

The G3 facsimile 3 that has received the above signal sends T, 30 procedure signals, NSS, TSL, and DC3 to the terminal adapter 2. For terminal adapter 2, LL, L2
The received signal from the terminal passes through the hybrid transformer 12, is converted into a digital signal by the A/D converter 16, is input to the ISDN communication control circuit 17, and is sent out to the ISDN via the B channel. .

After the B channel is turned on in this manner, transparent transmission of 7G3 facsimile 3 procedure signals and image signals is performed by the B channel.

After the communication of the G3 facsimile 3 via the B channel is completed, the disconnection procedure that was first performed by the calling terminal or the disconnection procedure that was first performed by the called terminal is performed.

First, the case where the calling terminal hangs up first will be explained.

When the communication of the G3 facsimile 3 is completed, the G3 facsimile 3 releases the DC loop. The DC loop detection circuit IO detects the release of the DC loop and notifies the ISDN communication control circuit 17 with a loop detection signal. Upon receiving this, the ISDN communication control circuit 17 turns off the B channel and executes a disconnection procedure with the ISDN. As a result, the terminal adapter 2 becomes disconnected from the ISDN.

Next, a case where the called terminal hangs up first will be explained.

In this case, after receiving a disconnection signal from the ISDN, it performs a disconnection procedure and turns off the B channel.

When the B channel is turned off, the B channel received signal from the network sent to the G3 facsimile 3 becomes silent.0 When a disconnection signal from the ISDN is received during communication, the G3 facsimile 3 ” is detected and a communication error occurs. If received after the end of the communication,
Even if the B channel reception signal becomes no signal, the process ends normally.

Next, the calling procedure of the terminal adapter 2 in the above embodiment will be explained.

FIG. 4 is a flowchart of a signal when the terminal adapter 2 receives a call.

First, a startup procedure from the network terminal device NT is performed, and the terminal adapter 2 enters the startup state.

Then, a link control procedure and a connection control procedure are performed.

Terminal adapter 2, which received the connection control procedure signal,
The ISDN communication control circuit 17 outputs a 16Hz transmission command to the 16Hz generation circuit 13.

The 16Hz generation circuit 13 generates a 16Hz signal and
The Hz signal is sent to the G3 facsimile 3 via terminals L1 and L2. The G3 facsimile 3 that has detected the 16 Hz signal captures the line by automatic or manual response, and a DC loop is formed. The DC loop detection circuit 10 detects the DC loop and notifies the ISDN communication control circuit 17 using a loop detection signal. Upon receiving this, the ISDN communication control circuit 17 turns on the B channel, and the signal of the G3 facsimile 3 is transferred via the B channel, as in the case of the above call origination.

By doing the above, it is possible to connect to the 15DN and perform mutual communication without modifying the existing 03 facsimile 3 device.

Note that the operation of the terminal adapter 2 in the disconnection procedure is the same as in the case of making a call.

[Effects of the Invention] According to the present invention, there is an effect that the G3 facsimile 3 can be connected to ISDN and perform mutual communication without modifying the G3 facsimile 3.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing in detail an example of the terminal adapter 2 in the above embodiment. FIG. 3 is a flowchart of signals when the terminal adapter 2 makes a call. FIG. 4 is a flowchart of signals when the terminal adapter 2 receives a call. FIG. 5 is a diagram showing a conventional device. 2...Terminal adapter, 10...DC loop detection circuit, 11...DC superimposition circuit. 13...16Hz generation circuit, 14...Dial signal identification circuit, 17...I SDN communication control circuit. NT...Network termination equipment.

Claims (1)

[Scope of Claims] Means for detecting a hook-up state of a G3 facsimile by superimposing a direct current on a connecting portion with the G3 facsimile; A means for receiving a dial pulse or a DTMF signal sent from the G3 facsimile and transmitting the signal to an ISDN. means for converting into a call procedure; A/D conversion means for converting the procedure signal and image signal from the G3 facsimile into digital signals; means for transmitting the digital signal via the B channel of the ISDN; means for notifying the G3 facsimile of the incoming call when there is an incoming call from the ISDN;
3. An ISDN terminal adapter comprising: D/A conversion means for converting facsimile procedure signals and image signals into analog signals.