JPH0420035A - Data transmission system - Google Patents

Abstract

PURPOSE:To freely use a network control code by representing the off-state of a control signal according to the alternate pattern of status bits and allowing a reception side to discriminate the off-state of the control signal depending on the deviation between the alternate pattern and 'Os' pattern. CONSTITUTION:Data communication is implemented between data terminal equipments(DTEs) 1, 10. The ON-state of a control signal is represented by '1s' of status bits and the off-state of the control signal is represented by the alternate pattern of the status bits, then the control signal is sent, the '1' of the bits is received as the ON-state of the control signal and the off-state of the control signal is received as the alternate pattern or '0'. Thus, the use of a network control signal is implemented freely even when a similar logic combination to that of the network control code takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control signal transmission system applied to a high-speed digital dedicated line connected to a public communication network.

[Conventional technology]

Generally, on high-speed digital dedicated lines, data and control signals from terminal equipment are configured as frames called envelopes, and transmitted in units of frames.Furthermore, the envelopes of these lines are multiplexed and transmitted. It has become something to do.

FIG. 3 is a diagram that does not show the configuration of the envelope.

A first framing bit F, followed by a plurality of data bits D, ~D6 . The status bit S added at the end constitutes an envelope E. In high-speed digital dedicated lines, the ON state of the control signal is indicated by the status bit S "1", and the OFF state of the control signal is indicated by the "1" of the same bit S. 0'', and data bits D1-D when the same signal is off.

is fixed to "1" and transmitted.

In addition, a network control code is used to indicate transmission status failures and during testing on the transmitter side, and the code during testing includes "FO
OIOloo” UNR code.

A DNR code of "FOOOOOOOOO" is determined for each fault code, and these codes are transmitted when the control signal is off.

[Problem to be solved by the invention] 4 However, when a high-speed digital private line is connected to a general public line, data is transmitted based on the CCITT recommendation X21 interface regardless of whether the control signal is on or off. Since there is a possibility that logical value combinations similar to the network control code may occur during data transmission, there is a drawback that the network control code cannot be used.

[Means to solve the problem]

The present invention is constructed by the following means.

That is, in the above-described system, the ON state of the control signal is indicated by the status bit "l"';

The OFF status of the control signal is indicated by the alternating pattern of the status bit and transmitted, and the status bit ``1'' is received as the ON of the control signal [7], and the alternating pattern of the status bit or ``0'' is indicated as the OFF of the control signal. It is assumed that it will be received as follows.

[For production]

Therefore, since the OFF of the control signal is indicated by the alternating pattern of the status bits, there is no confusion with "0", and on the receiving side, both the alternating pattern and 0'' are judged as the OFF of the control signal. A reset operation can also be performed to turn off the control signal using the network control code.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 2 is a block diagram of a system to which the present invention is applied, including a data terminal equipment (hereinafter referred to as DTE) 1 and a multiplexer (
Hereinafter, the connection with MPX) 2 is based on the X21 interface, and the connection between MPX 2 and MPX 4 is through a high-speed digital dedicated line (hereinafter referred to as dedicated port m) 5.

MPX4 is connected to public communication #17 via data communication equipment (hereinafter referred to as DCE) 6, and connected to DCE8 via surrounding network 7, and DCE8 is connected to D'l'E10 based on the X21 interface. It is.

With these configurations, data communication is performed between the D'I'EI and the DTE IO.

Figure 1 is a block diagram showing the main parts in Figure 2.
A relay station (hereinafter referred to as "relay station") is installed between PX2 and MPX4.

REP) 21 has been inserted into MPX2.

The DTEL transmits data 1' and the control signal C, while the 1MPX4 transmits the DTEL via the public communication network 7.
Reception data R and reception control signal i to TEL 0 are to be sent.

The control signal C is an S bit encoding circuit (hereinafter referred to as BCD) 2
In 2, on is "l" and off is "l・0" or "0・
After being converted into a status bit S according to an alternating pattern of
Here, it is configured as an envelope E together with the transmission data T, and a UNR conversion circuit (hereinafter referred to as
UNC) 24, a multiplex circuit (hereinafter referred to as MPC) 25
is multiplexed with similar signals from other channels and transmitted to dedicated port 1IIA5a.

The REP 21 includes a DNR conversion circuit (hereinafter referred to as DNC) 26.
is provided, which converts the envelope E into a DNR code in response to the occurrence of a failure before the dedicated cycle $1j5a.

The multiplexed signal from MPX2 via REP21 passes through dedicated port wA5b and reaches MPX4, where a separation circuit (hereinafter referred to as DMX) 27 converts the multiplexed signal into a signal for each channel, and an envelope separation circuit (hereinafter referred to as DMX).

ED~') 28, the received data R and the status bit S are separated, and the status bit 8 is
The bit decoding circuit (hereinafter referred to as 5DC) 29 outputs "l"
is on and an alternating pattern of 1.0" or "0.1" is decoded into a reception control signal I in which it is off and then sent out.

In addition, a DNR detection circuit (hereinafter referred to as DND) 30 and a UNR detection circuit (hereinafter referred to as UND) are connected in parallel with the input of EDV28.
31 are connected, and these allow the network control code D
It detects that three envelopes of the NR code and UNR code are consecutive, and lights up the display light emitting diodes 32 and 33, respectively.

Here, the DND 30 and the UND 31 receive the status bit l'' as is, while receiving the same bit as an alternating pattern of 0''.

Therefore, if MPX2 is in a test state, UN
The C24 converts the envelope E into the UNR code and sends it out, but since the status bit S of the code is sent out in an alternating pattern, this is definitely received as "0" at the UND31, and the status bit S'h
The same code can be accurately received without recognizing other envelopes EfP and J that are t″0″.

Also, if a failure occurs before dedicated port #115a,
The DNC 26 of the REP 21 converts the envelope E into a DNR code and sends it out, but at this time the status bit S
is sent in the alternating pattern, so D
Accurately received by ND30.

On the other hand, since the 5DC 29 also receives the alternating pattern of the status bit S as "0", this also resets the reception control signal I, making it suitable.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the ON state of the control signal is indicated by "1°" of the status bit,
In addition, the OFF state of the control signal is transmitted by indicating the alternating turn of the same bit, and the same bit '1' is received as the ON state of the control signal.

By receiving an alternating pattern of the same bits or "0" as off, the network control signal can be used freely even when a logic value combination similar to the #1 control code occurs. This method does not cause any trouble in resetting the system, and a remarkable effect can be obtained on high-speed digital private lines connected to general public lines.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the invention. FIG. 2 is a block diagram of the main parts, FIG. 2 is a block diagram of a system to which the present invention is applied, and FIG. 3 is a diagram showing the configuration of a commonly used envelope. 1.10... Data terminal equipment, 2.4... Multiplexing device, 5.5a, 5b... High-speed digital dedicated line, 7... Public line, 21... Relay Bureau, 22.
... S bit encoding circuit, 24 ... U N R conversion circuit, 26 ... DNR conversion circuit, 29 ... S
Bit decoding circuit, 30...DNR detection circuit, 31
...U N n detection circuit, E ... envelope, S ... status bit.

Claims (1)

[Claims] In a method in which an envelope is configured by a framing bit, a plurality of data bits following the framing bit, and a status bit added at the end, and data is transmitted using the envelope as a unit, the control signal is turned on when the status bit is set to "1". ”, and the OFF of the control signal is indicated by the alternating pattern of the status bits, and the status bit “1” is received as the ON of the control signal, and the alternating pattern of the status bits or A data transmission system characterized in that "0" is received as an off state of the control signal.