JPS6072445A - Data exchange between modem for 4-wire private line and data terminal device for digital line exchange network - Google Patents

Abstract

PURPOSE:To attain data exchange by providing three latch circuits to an exchange to allow the latch circuits to synchronize with three kinds of timing signals, and to transmit and receive data with an MODEM and a terminal device, thereby allowing the terminal device to satisfy the interface condition between MODEMs. CONSTITUTION:A reception signal element timing signal RT from the MODEM 13 is inverted at an inverting device 14 and inputted as the 1st timing signal, the clock of a clock generating circuit 24 is transmitted to the MODEM13 as a transmission signal element timing signal ST1 (2nd timing signal) to the MODEM13, and further the said clock is transmitted to a terminal device D- DTE11 via an inverting device 40 as the signal element timing signal S for transmitting and receiving data between the MODEM13 and the D-DTE11. Thus, the interface condition of the CCITT recommendation is satisfied both at the D-DTE11 and the MODEM13 sides.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a modem for a 4-wire private line (hereinafter referred to as a modem) and a data terminal device for a digital circuit switching network (
The present invention relates to a data exchange device used when exchanging data between D-DTEs (hereinafter referred to as D-DTEs).

[Technical background of the invention]

In a conventional system using a 4-wire leased line as the transmission medium, data exchange between a modem and a modem controller that controls the modem is conducted in accordance with CCITT Recommendation, V. Based on 29, the following was done.

That is, when the modem control device sends data, it synchronizes the transmission data SD with the transmission signal element timing signal 3 given from the modem control device 1 to the modem 2 as shown in FIG. Then, the modem 2 takes in the signal, or the modem 2 takes it in synchronization with the transmission signal element timing voice signal 4 given from the modem 2, which is indicated by a broken line. On the other hand, from modem 2 to modem control device 1
When transmitting data, the modem control device 1 takes in the received data RD in synchronization with the receiver element timing signal 5 given from the modem 2, as shown in FIG. 1(B).

Thus, CCITT Recommendation, V. 29, data exchange is performed between the modem and the modem controller based on the exchange of a transmit signal element timing signal and a receive signal element timing signal (these two timing signals do not necessarily have to be different signals). The rules are set.

On the other hand, in digital circuit switching networks that have become popular in recent years, D-DTE is used without using a modem, as per the CCITT recommendations.
X. 21, it is possible to access the digital circuit switched network. That is, as shown in Figure 2, D
- The DTE 7 is connected to a line connection terminal device (not shown) through a Sakai signal line T, a reception signal line R, a signal element timing signal line S, a control line C, and an identification line I, and transmits a transmission credit and a reception signal. is transmitted and received based on the signal engagement timing signal given from the line connection terminal device.

By the way, the digital circuit switching network has the above-mentioned D-
The DTE can be connected via a digital line, and can also be connected via the aforementioned four-wire side line. Therefore, there is a possibility that a digital line and a four-wire dedicated line may be connected together in a digital line switching network. Therefore,
In this case, there is a desire to connect the D-DTE to both the digital line and the four-wire dedicated line to perform data communication without making any changes to the D-DTE.

[Problems with the background art]: However, even if the D-DTE is not connected to the four-way system, the D-DTE is still compatible with the CCITT recommendations, X. According to CCITT Recommendation, V.21, there is only one signal element timing signal. 29, it was not possible to connect the above-mentioned D-DTE to a modem that required both a transmit signal element timing signal and a receive signal element timing signal.

[Purpose of the invention]

The present invention was made in response to the above-mentioned demands, and its purpose is to satisfy the interface conditions when connecting the D-DTE to the modem and to enable data exchange between the D-DTE and the modem. It is an object of the present invention to provide a data exchange device between a modem (for a four-wire leased line) and a D-DTE.

[Summary of the invention]

Therefore, in the present invention, a first timing signal, which is a received signal element timing signal given from the modem, which is necessary when taking in data from a modem for a 4-wire private line, and a first timing signal, which is a received signal element timing signal given from the modem, A device that transmits and receives data based on the timing of a necessary second timing signal and a third timing signal that is necessary when transmitting and receiving data between a data terminal device for a digital circuit switching network, The launch of axis 1 is used to capture data from the modem in synchronization with the third timing signal, and to send the captured data to the digital circuit switching network data terminal device in synchronization with the third timing signal. and the data terminal device for the Digimol line switching network in synchronization with the third timing signal, and transmitting the captured data to the modem in synchronization with the second timing signal. A second latch circuit is provided to configure a data exchange device between a modem for a 4-wire dedicated line n and a data terminal device for a digital circuit switching network, thereby achieving the above object.

[Embodiments of the invention]

FIG. 3 is a block diagram of a system in which a D-DTE II and a modem 13 are connected using the apparatus of the present invention. D
-DTell is connected to the data exchange device 12 by a cable 15 consisting of each control signal line and data line,
The modem 13 is connected to the data exchange device 12 by a cable 16 consisting of control signal lines and data lines.

Furthermore, the modem 13 is connected to a network control unit (hereinafter referred to as NC) via an output data line 17'al (human data line 171).
(referred to as U) 14, and the NCU 14 is connected to four-wire dedicated lines 18a and 18b.

In such a system, the NCU 14
At the command of Ell, the 4-wire dedicated line isa, ta
For example, the digital circuit switching network connected to b is activated or restored. The data sent from the D-DTEII reaches the data exchange device 12 via the cable 15,
The data exchange device 12 is connected to the modem 13 via a cable 16. Here, the data is modulated and output via the output data line 17a and the NCU 14f to the 4-wire dedicated line 1.
8a. Additionally, data to be received by the D-DTE 11 is transmitted via a four-wire dedicated line 'ffa1sb' to the NCU 14, and from the NCU 14 to the modem 13 via an input data line 17b. Here, the data is demodulated, and the demodulated data is transmitted via the cable 16, the data exchange device 12, and the cable 15 to the D'-DT
Incorporated into EII. Here, the data exchange device 12 uses CCITT Recommendation X between the data exchange device 12 and the D-DTE II. 2
1, and with the modem 13, it satisfies the interface conditions of ccIT'r Recommendation, 29.

FIG. 4 is a block diagram of one embodiment of the present invention. In this embodiment, the first latch circuit is connected to the third latch circuit 2.
1. It consists of two fourth latch circuits 22. The third latch circuit 21 receives the received data RD given from the modem 13 via the received data signal line 25, and receives the received signal element timing multi-degree signal given from the modem 13 via the received element timing signal line 26 and the inverter 41. R
Latch in synchronization with T. The output data of the third latch circuit 21 is latched by the fourth latch circuit 22 in synchronization with the clock output from the clock generation circuit 24. The output signal line 27 of this fourth latch circuit 22 is D-D
The output data R'e and D-DTEll of the output signal a27 are taken in in synchronization with the signal element timing signal S of the signal element timing signal line 28. This signal element timing signal S is synchronized with the clock output from the clock generation circuit 24 and is obtained via the inverter 40. Also, in synchronization with this signal element timing signal S, D
-DTEll sends out input data T via the input signal line 29 for the second latch circuit 23.

The second latch circuit 23 takes in the human input data T in synchronization with the clock output from the clock generation circuit 24.

Further, the clock output from the clock generation circuit 24 is used as the transmission signal element timing signal ST of the modem 13.
1 is applied from the transmission signal element timing signal line 31 to the modem 13. The modem 13 is provided via the transmission signal element timing signal line 31, and synchronizes with the transmission signal element timing signal STt.
Transmission data SD is input from the second latch circuit 23 via the transmission data line 30.

In this embodiment, the received signal element timing signal RT given from the modem 13 is inverted and input as the first timing signal by the inverter 41, and the clock output from the clock generation circuit 24 is input to the modem 13. As a second timing signal, which is a transmission signal element timing signal ST1 necessary when sending data to
The clock signal is sent to the modem 13 and further outputted from the clock generation circuit 24 through the inverter 40 as the signal element timing signal S required when transmitting/receiving data between the D-DTE II. and sends it to D-DTEII. Therefore, on the D-DTEll side, the CCITT recommendation that data is sent and received using one timing signal,
21 is satisfied, and on the modem 13 side, the CCITT recommendation v29 interface condition of transmitting and receiving data using a 2''':) timing signal is satisfied.

In this embodiment, since the clocks of the black and white generation circuit 24 are the transmission signal element timing signal STs and the signal element timing signal S, the clock generation circuit 111 can be configured with a circuit that generates a single clock.
The second type is one in which only one sub circuit 23 is required. Therefore, two clocks may be generated from the clock generation circuit, another latch circuit may be connected after the second latch circuit 23, and the operation of this latch circuit may be performed using the other of the above clocks. .

In this embodiment, the received signal element tie-inter signal R
It is assumed that T and the transmission signal element timing signal ST are in phase.

FIG. 5 is a schematic diagram of another embodiment of the present invention. Components that are the same as those in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, the output from the circuit for generating the transmission signal element timing signal ST included in the modem 13 is transferred to the second latch circuit 23° inverter 410''!c.
The fourth channel is supplied to the child circuit z2 through the fourth channel. That is, the transmission signal element timing signal line 3
2, the fourth latch circuit 22 latches the output data of the third latch circuit 21, and also latches the output data of the third latch circuit 21. takes in the output data R of the fourth latch circuit 22 and also sends out the input data T. The second latch circuit 23 latches the transmission signal element timing signal ST! in synchronization with the transmission signal element timing signal STx, while the second latch circuit 23 latches the transmission signal element timing signal ST! In synchronization with the second. Now, child circuit 23
The transmission data SD, which is the output data of the transmission data line 3. Enter 100 through q.

In this way, in this embodiment, the reception (g element timing signal RT) given from the modem 13 is inverted and input by the inverter 41 as the first timing signal, and the modem 13 receives the Transmission 4 elements 1 -.

The element timing signal STx is used as the first timing signal required when transmitting the one mode 13 hetator, and the transmission signal element timing signal ST3 is set as
D is passed through the inverter 40 as the signal element timing signal S required when transmitting and receiving data between the TELL and the TELL.
- Send to DTell. Therefore, on the D-DTEll side, data is sent and received using one timing signal.
The interface conditions of CITT Recommendation X, 21 are satisfied, and the interface conditions of CCITT Recommendation, V, 29 of transmitting and receiving data using two timing signals on the modem 13 side are satisfied.

FIG. 6 is a block diagram of another embodiment of the invention. FIG. 4, Wl; Components that are the same as those in the figure are given the same reference numerals, and explanations thereof will be omitted.

In this example, the reception received from the modem 13 is as follows:
1. The transmission signal element tying signal RT is transmitted to the fourth latch circuit 2 via the second slave circuit 2A and the inverter 40.
It is designed to give 5 points.

Immediately, receive ←receive signal given from mode + di via timing signal line 26□)
In synchronization with timing -RT, the fourth latch circuit 22 converts the output data of the i-th child circuit 21 into 1. At the same time as latching, the D-DTEll takes in the output data R output from the fourth latch circuit 22.

Further, in synchronization with the received signal element timing signal RT given from the modem 13, the D-DTE II sends out the input data T, which the second latch circuit 23 receives from the modem 13. The received signal element is latched in synchronization with the timing signal RT. Furthermore, the modem 13
The received signal element timing signal RTe is transmitted via the transmitted signal element timing signal line 31 as the transmitted signal element timing signal ST1, and the transmitted data SD, which is the output data of the second latch circuit 23, is sent to the transmitted data line in synchronization with the received signal element timing signal RTe as the transmitted signal element timing signal ST1. 30.

As described above, in this embodiment, the n received signal element timing signals RT given from the modem 13 are inverted and inputted as the first timing signal by the inverter 41, and this signal is used when transmitting data to the modem 13. The transmission signal element timing signal S which is the second timing signal
In addition to Tl, the signal element timing signal S required when transmitting and receiving data with the D-DTEll.
The signal is sent to the D-DTEII via the inverter 40.

Therefore, on the D-DTEll side, the CCI'f'T Recommendation,
Modem 13 (11
:i means CCITT'! that data is sent and received using two timing signals (in this embodiment, there are two similar timing signals). The interface conditions of II, V, 29 are satisfied.

In this embodiment, since the received signal element timing signal RT and the signal element timing signal S are synchronized, the fourth latch circuit 22 is not necessarily necessary, and the output of the third latch circuit 21 is , it is also possible to use the 1 inch output data R.

Embodiment 01 of the data exchange device as described above may be used singly, but two or three of these may be provided in the same device and switched by hardware or software to enable communication between the calling side and In this case, the most suitable data exchange device may be selected for the called party.

For example, on the calling side? P, Data exchange equipment R shown in Figure 4
If the data exchange device shown in FIG. 6 is used on the called side, the timing signal generated and sent by the clock generation circuit 24 from the calling side is transmitted to the called side. As is clear from FIG. 6, the called side uses the reception timing signal as the transmission timing signal.

Therefore, the timing signal for receiving the call (11) is generated by its own clock generation circuit 24, and the timing signal is returned out of phase. Therefore, although there is a phase difference between the transmitting timing signal and the receiving timing signal, it is only necessary to detect the received data by considering the phase difference, since the frequency is the same, and the frequency is different (fluctuation). The received data can be easily detected compared to the case where the received data is detected in the case of

Still, in both embodiments, the D-DTE can be used without adding special signal lines to the D-DTE or the modem.
, a modem can be used.

〔Effect of the invention〕

As explained above, according to the present invention, the interface conditions can be satisfied between the D-DTE and the modem (for a 4-wire dedicated line) without making any changes to the D-D'TE. data can be exchanged.

[Brief explanation of the drawing]

Figure 1 is a block diagram for explaining the interface conditions between a 4-wire private line modem and its control device, Figure 2 is a block diagram for explaining the interface conditions for D-DTE, and Figure 3 is for explaining the interface conditions for the D-DTE. 1 is a block diagram of a system using the apparatus of the present invention, and FIGS. 4 to 6 are block diagrams each showing an embodiment of the present invention. 21... Third latch circuit, 22... Fourth latch circuit, 23... Second latch circuit, 24... Black,
Regeneration circuit, 40.41...Inverter agent Patent attorney
Book 1) Takashi

Claims (5)

[Claims] (1) A first timing signal that is a received signal element timing signal given from the modem, which is necessary when taking in data from a modem for a 4i dedicated line;
Data is transmitted based on the timing of a second timing signal required when transmitting data to the modem and a third timing signal necessary when transmitting/receiving data between the data terminal device for the digital circuit switching network. A transmitting/receiving device that receives data from the modem in synchronization with the first timing signal, and transmits the received data to the digital circuit switching network in synchronization with the third timing signal. A first latch circuit for sending data to a terminal device receives data from the data exchange device 1 for the digital circuit switching network in synchronization with the third timing signal, and transmits the received data to the first latch circuit. a second timing signal for transmitting to the modem in synchronization with the timing signal of No. 2;
A data exchange device between a modem for a four-wire dedicated line and a data terminal device for a digital line switching network, comprising a latch circuit. (2) The first latch circuit is composed of two child circuits, a third and a fourth, and is connected to the third latch circuit in synchronization with the first timing signal for a four-wire dedicated line. Claim 1, characterized in that the data from the modem is taken in, and the fourth latch circuit is made to take in the output data of the third latch circuit in synchronization with a third timing signal. A data exchange device between a modem for a four-wire dedicated line described in item 1) and a data n1 terminal device for a digital recollection exchange network. (3) For use in a four-wire dedicated circuit according to claim (1) or (2), wherein the second and third timing signals are generated in the Iff y error generation circuit. A data exchange device between a modem and a data terminal for a digital circuit switching network. (4) Claims (1) or (2) characterized in that the second and third timing signals are transmission signal element timing signals possessed by a modem for a four-wire dedicated line. A data exchange device between the modem for the four-wire private line described above and a data terminal device for a digital circuit switching network. (5) Convert the second and third timing signals to the first signal element timing signal, which is the received signal element timing signal provided from the modem.
A data exchange device between a four-wire dedicated line and a data terminal device for a digital circuit switching network as claimed in claim (1) or (2), characterized in that the timing signal is a timing signal of: