JPS59141897A - Processing system of signal bit - Google Patents

Abstract

PURPOSE:To multiplex a sound call and a data call to a PCM transmission line for an exchange system having a multiplexed PCM transmission line by changing a signal bit position for a terminal to another position which is different from an exchange control bit position. CONSTITUTION:When the data on a subscriber line interface of (F+D1-D6+S) bits is sent from a terminal side, a line circuit holds the data blocks of every 8 bits at a shift register RA by a clock (a). Then (D1-D6+S) bits are shifted by one bit excepting the F bit and stored in a shift register RB to be delivered to the side of an exchange EX1 by a clock (b). The EX1 puts the data of 7 bits into a prescribed channel and then transmits the data to a transmission line after adding a signal bit of exchange control to the final bit position.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a digital data transmission system, and particularly relates to signal bit processing in data transmission between data terminals via a digital exchange and a PCM transmission line. .

(2) Background of the technology With the diversification of communication data, digital exchanges have been introduced in switching networks, and with the multiplexing of transmission paths, switching systems using PCM lines have been developed. The digital exchange and the transmission line are interfaced with, for example, 8-bit PCM encoding for each multiplexed channel, and as shown in Figure 1, a voice call consists of 12 multiframes i, b, i, and frame is 2
It consists of 4 channels (CH) and a synchronization bit S, and 8 bits (4) are used for each line as audio digital information. For example, 1 bit (B) of the 8 bits is used as a signal every 6 multiframes. P is used as a switching side, a starting 9 selection signal, a response signal, etc. for a proboscised line.
A CM24B transmission line or the like is used.

(3) Prior Art and Problems On the other hand, in the transmission and reception of data between general data terminals, as shown in FIG. 2, a synchronization bit F is used.

Data is exchanged in units of one block consisting of 8 bits of data (9 bits) (D, to D0) and control signal bits S of the terminal device.

Since this data terminal sends and receives data using a dedicated line that connects the terminals without going through an exchange, it is controlled independently of voice call transmission, and the transmission format shown in Figure 2 is used to transmit and receive data over the dedicated line. transmission is possible, but it is important to make effective use of the transmission path and to transmit voice calls, facsimile calls, and data calls on the same exchange
In order to improve the service of multiplex communication to the CM line, the PCM transmission line should be replaced with η + 6 bits of data + (S bit of the group is the signal bit for exchange control) shown in Figure 2. Therefore, a problem arises in that data calls cannot be transferred across the transmission range.

Therefore, it is not possible to connect a voice or FAX call to one channel at any given time, and a data call at another time, and it is not possible for the exchange to handle voice calls and data calls in the same way.

(4) Purpose of the invention The purpose of the present invention is to solve the above problems, and to
The object of the present invention is to provide a signal bit processing method that allows voice calls and data calls to be multiplexed on a transmission path, and further enables transmission on the exchange side without distinguishing between voice calls and data calls on the interface of the transmission path.

(5) Structure of the Invention In order to achieve the above object, the present invention provides that data transmission and reception between a data terminal and a digital exchange is performed in a data format that includes signal bits for the terminal, and that data between the digital exchange and other stations is transmitted and received. In an exchange system in which transmission and reception are performed using a multiplexed PCM transmission line containing exchange control bits as an interface, the present invention is characterized in that means is provided for changing the position of the signal bit to a position different from the position of the exchange control bit.

(6) Examples of the invention The present invention will be explained below using examples.

As explained earlier in Figure 2, the information sent and received between data terminals only needs to be 6 bits of data and 7 bits of signal 3', and the F bit is used for synchronization at the interface between terminals or between terminal exchanges. This is used as a service bit and is not needed for other purposes. The present invention focuses on the fact that a total of 7 bits, including 6 data bits and S bits, required by this data terminal need only be guaranteed on the exchange and on the transmission path.

FIG. 3 shows an example of the configuration of an exchange system to which the present invention is applied. In the figure, DTE is data terminal equipment,
DCE is a terminal terminal equipment, LC is a line circuit, EXI is a digital exchange, DT is a trunk, EX2 is a counterpart digital exchange, etc.

Data is transmitted and received A between the terminal DTE and the exchange EXI in the data format shown in FIG. 2 (hereinafter referred to as the subscriber interface). In addition, the transmission line interface between EXI and EXZ between exchanges uses the transmission format shown in Figure 1 (for example, P
CM24B).

In such a configuration, the present invention converts data when inputting it from a terminal to an exchange or inputting it to a transmission path when data is transferred to transmission path C via an exchange, and vice versa. This is accomplished by inverting the data when sending it.

An embodiment in which a signal bit processing method, which is data conversion of the present invention, is applied to a line circuit LC will be described below with reference to FIGS. 4 and 5.

Figure 4 explains the bit shift processing when sending data from the terminal to the exchange, CF+D, ~Da+S
) is sent from the terminal side, the line circuit LC holds the data block in units of 8 bits in the shift register RA using the clock ■, and then removes the F bit and transfers it to [D1~ D6+S, 1 is shifted by 1 bit, stored in the shift register RB, and sent to the exchange EXI side by the clock ■. The exchange EX1 inserts this 7-bit data into a predetermined channel (the channel assigned to the receiving terminal side), and adds a signal bit number for exchange control to the last bit position of the channel as shown in Figure 1. Send to the transmission path.

Figure 5 explains the bit shift processing when sending data from the exchange side to the terminal, in which 8 bits of data on a predetermined channel (channel captured for the originating terminal) are extracted from the transmission path, and the line Send to circuit LC. In the line circuit Lc', the 8 bits of bits are held in the shift register RC by the clock ■, and then the synchronous pit F is stored in the shift register RD by the clock ■, and the contents of the register RC are shifted by 1 bit and transferred to the shift register RD. Store. Based on the clock (2), the contents of the shift register RD are sequentially sent to the terminal side.

In this way, when establishing a transmission line interface on the exchange side, data blocks from data terminals can be transferred to S by adding control pitnos to the 7-bit data without any identification, similar to voice calls. B.

can be sent to the transmission path without destroying the port.

In this ζ, the clocks ■ and ■ are inserted into the time-division highway and set the timing for extraction.For example, if the highway in the exchange is 32 multiplexed (2,048 mb/S), the gate circuit G2. It will be controlled in synchronization with the 32 lines of G and Hato. Also, the clock ■■ is the terminal terminal equipment DC.
The timing is determined by the exposure of the transmission block between E and the line circuit LC, and gates GI and G4 are opened and closed according to this timing.

Figure 6 shows an example of the highway HW of this digital exchange, in which one frame (125 μg) is multiplexed 32 times (32 lines) and each time slot) TSO to TS, 31
is composed of 8 bits.

In the above embodiment, bit foot processing is performed as pit processing, but it is not limited to this. As shown in FIG. 7, the position of the F bit of the subscriber line interface format is It may also be a conversion to move to a position corresponding to the control pit (B) of the interface format.

Further, in this embodiment, an example in which bit processing is performed in the line circuit LC has been described, but the bit processing may be provided in an interface circuit (for example, a trunk) between an exchange and a transmission line.

In addition, in this embodiment, PCM is used as the transmission line interface.
Although the explanation has been made using a 24B configuration, it goes without saying that the present invention can be applied to any transmission system that uses one bit in one channel for switching control. According to the present invention, in a switching system having a multiplexed PCM transmission line connected to a digital exchange, the button is also used for switching control when connecting a data terminal having an interface different from the transmission line interface 7Ax. The signal pit (B) does not destroy the signal pit (S) required on the data terminal side, and eliminates the need for control to distinguish between voice calls and data calls at the exchange, allowing the same exchange as for voice calls. Processing allows data calls to be handled.

[Brief explanation of drawings]

Figure 1 is a diagram showing the signal format of the transmission line interface, Figure 2 is a diagram showing the signal format of the subscriber line interface, Figure 3 is a diagram showing the configuration of a switching system to which the present invention is applied, Figures 4 and 5. 6 is a diagram showing an example of the configuration of a highway HW of an exchange, and FIG. 7 is a diagram showing another example of signal pit processing. DTE: Data terminal DCE: Terminal termination equipment LC; Line circuit EXI; Digital exchange DT; Trunk EX2; Opposite digital exchange

Claims (1)

[Claims] Data transmission and reception between a data terminal and a digital exchange is performed in a data format that includes a terminal signal bit, and data transmission and reception between the digital exchange and other stations is performed using an inter-7A transmission line that includes an exchange control bit. 7. A signal bit processing method according to claim 7, further comprising a means for changing the signal bit position to a position different from the exchange control bit position in an exchange system performed as an exchange control bit.