JPS6284639A - Synchronous modem loop device - Google Patents

Abstract

PURPOSE:To make a mutual communication between terminals connected to a synchronous analog modem side and a digital subscriber line side which use different operation clocks by compensating the shift in operation clock frequency between the synchronous analog modem side and a digital exchange side by an elastic memory(ES). CONSTITUTION:When transmission data SD is transmitted from the digital exchange side to the SAMD side and loading data SD is inputted to MSPT 100 from the digital exchange 300 while a down time slot has a specific signal format, a signal processing part 120 extracts the transmission data SD and a request to send RS from an input data signal and inputs them to an ES part 110, and a write clock ST1 synchronized with the operation clock on the side of the digital exchange 300 with the data signal to write the transmission data SN in the ES part 110. At this time, the transmission request signal RS is sent out to the side of the SAMD 200. Then, the data is written in the ES part 110 when the RS is on.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems (Fig. 1) Effect (Fig. 2) (A ) When transmitting data SD is transmitted from the digital exchange side to the synchronous analog modem side (B) When receiving data RD is transmitted from the synchronous analog modem side to the digital exchange side Example (Figures 2 to 4) (a) Explanation of configuration (bl) Explanation of operation (b-1) When transmitting data SD from the digital exchange side to the synchronous analog modem side (b-2) When transmitting received data RD from the synchronous analog modem side to the digital exchange side Effects [Summary] A synchronous modem pool device is configured using elastic memory (ES), and this ES compensates for the difference in operating clock frequency between the synchronous analog modem side and the digital exchange side. This enabled mutual communication between terminals connected to different synchronous analog modem and digital subscriber line sides.

[Industrial application field]

The present invention relates to a synchronous modem pool device connected between a digital exchange and a synchronous analog modem, and for allowing mutual communication between terminals connected to the synchronous analog modem and the digital subscriber line.

[Conventional technology]

In recent years, digital exchanges have completely digitized the interior of exchange networks, and subscriber lines are also being digitized.

In a digital switch, each channel is 64kbp
It is an all-digital switching system with a transmission capacity of 500 s. Therefore, when each terminal connected to a digital subscriber line communicates with each other via a digital exchange, mutual communication can be performed by converting the signal format of each terminal into a 64 kbps universal signal.

On the other hand, the signal format on the analog line is p
It is a digital signal such as -1aw or A-1awPcM code. Therefore, traditional analog modem and NCU
(Network Control Unit: 1
In the case of switching between data lines connected to analog subscriber lines and data lines of digital subscriber lines, the above-mentioned conversion is not possible. Performed signal formant conversion.

A modem pool device is a conversion trunk that is connected between a digital exchange and a modem and is used to perform mutual communication between a terminal connected to the modem and a terminal connected to a digital subscriber line.

Conventionally, this modem pool device has been used to connect start-stop analog modems to digital exchanges.

The start-stop analog modem is a modem that transmits data using the well-known start-stop synchronization method. When connecting this start-stop analog modem to a digital exchange, data from the start-stop analog modem is sampled at multiple points using the operating clock of the digital exchange. was detected. This makes it possible to easily convert the μAaw PCM code of the start-stop analog modem to the signal format of the digital exchange without having to worry about the frequency or synchronization relationship between the clock of the start-stop analog modem and the clock of the digital exchange.

[Problem that the invention seeks to solve]

Analog modems include start-stop analog modems and synchronous analog modems (hereinafter abbreviated as SAMD); the former is mainly a low-speed modem, and the latter is a high-speed modem (2.4 kbps).
above) modem.

However, as mentioned above, conventional modem pool devices were designed for start-stop analog modems, so even though SAMDs have become more popular in recent years as modem speeds have increased, it has not been possible to convert them into digital exchanges. There was a problem in that it was not possible to connect and communicate with terminals on the digital subscriber line side.

SAMD communication has conventionally been transmitted using a normal analog circuit switching method, and a modem pool for SAMD has not been realized so far.

An object of the present invention is to provide a modem pool device for SAMD.

[Means for solving problems]

The means taken by the present invention to configure a synchronous modem pool device (hereinafter abbreviated as MDPT), which is a modem pool device for SAMD, will be explained with reference to FIG.

FIG. 1 is a block diagram showing the configuration of the present invention.

In Figure 1, 100 is MDPT, 200 is SAMD
, 300 is a digital exchange.

MDPTloo is located at the same level as a general trunk, and is a digital exchange that connects down highways and up highways (the highways are time-division multiplexed,
(consisting of an undefined number of time slots). Then, an elastic memory section (E
S section) 110 and a signal processing section 120, and also includes a signal processing section (CODEC
part) 140.

The 83 unit 110 writes the time slot white information input from the digital exchange 300 side inputted from the signal processing unit 120 using the write clock inputted from the signal processing unit 120, and writes the written transmission data SD to the time slot white information inputted from the SAMD 200 side. Read with read clock and SAMD20
0 side as transmission data SD, write the reception data RD input from the SAMD 200 side using the write clock input from the SAMD 200 side, and read the written reception data RD using the read clock input from the signal processing unit 110. I do.

In this case, the interface between SAMD200 and MDPTloo is that SAMD200 is Data City 11i Wholesaler DC
E, MDPT100 is commonly known as CC which is equivalent to data terminal DTE.
ITT recommendation V24. It has a transmission procedure such as V35. On the other hand, the signal processing unit 140 of MDPTloo and the SAMD200
This means that the SAMD 200 is a telephone terminal and the signal processing unit 140 is an analog line equivalent to a subscriber line.

The signal processing unit 120 performs the following processes (A) and (B).

(A) When transmitting the transmission data SD from the digital exchange 300 side to the SAMD 200 side, the transmission data SD is extracted from the downlink time slot inputted from the digital exchange 300 and inputted to the 83 section 110, and the data signal is transmitted from the digital exchange A write clock synchronized with the operating clock of the SAMD 300 side is generated and inputted to the SAMD 200 side, and a transmission request signal R8 is sent to the SAMD 200 side.

(B) When transmitting received data RD from the SAMD 200 side to the digital exchange 300 side, the read clock synchronized with the operating clock on the digital exchange 300 side is
3 unit 110, creates a predetermined signal format from the read received data RD, and sends it to the digital exchange 3.
Send to 00.

[Function] (A) When transmitting data SD from the digital exchange side to the SAMD side, the downlink time slot from the digital exchange 300 is in a predetermined signal format and the loaded data SD is MDPTIO.
When input to O, the signal processing unit 120 extracts the transmission data SD and transmission request R3 from the input data signal and inputs them to the 83 unit 110, and performs writing synchronized with the operating clock on the digital exchange 300 side from the data signal. The transmission data SD is written to the 83 section 110 by generating a clock ST.

At the same time, a transmission request signal R3 is sent to the SAMD 200 side. For writing to this 83 part 110, R3 is on (
ON).

Upon receiving the transmission request signal R3, the SAMD 200 sends 83
The transmission data SD stored in the unit 110 is sent to the SAMD 200.
Reading is performed using the operation clock RT.

(B) When transmitting the received data RD from the SAMD side to the digital exchange side, the SAMD 200 sends the write clock ST2 along with the received data RD and carry reception CD to
10, and receive data R at the write clock ST2.
Write with D. The writing to this 83 part 110 is C
This is done when D is in the ON state.

The signal processing unit 120 of MDPTI OO includes the ES unit 110
The reception data RD stored in the digital exchange 300 is read out using the operating clock ST of the digital exchange, and a predetermined signal formant is created and sent to the time slot of the digital exchange 300.

As described above, MDPTloo of the present invention can be converted into SAMD2
By providing it between 00 and the digital exchange 300, mutual communication can be performed between the terminals connected to the SAMD 200 side and the terminals connected to the digital exchange 300 side.

MDPTloo accommodates multiple SAMDs, but
By using the ES unit 110, it is possible to reliably compensate for the difference in frequency between the operating clock of each SAMD and the operating clock of the digital exchange 300.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 2 to 4.

FIG. 2 is an explanatory diagram of the configuration of a communication system using MDPTloo according to the present invention, FIG. 3 is an explanatory diagram of the configuration of an embodiment of MDPTloo, and FIG. 4 is an explanatory diagram of the configuration of an embodiment of MDPTloo. It is an explanatory diagram.

fa) Configuration description In FIGS. 1 and 2, MDPTloo, synchronous modem 200, digital exchange 300, MDPT 100
an elastic memory section (ES section) 110 in
The signal processing section 120 is as described in FIG.

In FIG. 2, 310 is a terminal (DTE) on the digital subscriber line side. 320 is a data adapter device (D
ate Adaptor Llnit: D A U
) has a connection interface between the terminal 310 and V24/35 to exchange data, and sends and receives the data to and from the digital subscriber line 330.

340 is a digital line circuit (DLC") that converts the data received from the digital subscriber line 330 into a known next-group 64 kbps universal signal and sends it to the digital exchange 300, and also converts the data received from the digital subscriber line 330 into a universal signal of 64 kbps, which is transmitted from the digital exchange 300. The universal signal is time division multiplexed and sent to digital subscriber line 330.

350 is an analog subscriber side terminal (DTE).

360 is an analog modem (MD), terminal 350 and V
It has a 24/35 connection interface to send and receive data. 370 is a network control device (Network Con
Trol Unit (NCU) controls the connection between the analog modem 360 and the analog subscriber line 380. 390 is an analog line circuit (ALC) that converts analog data received from the analog subscriber line 380 into a digital signal suitable for processing by the digital exchange 300, for example, a μAaw PCM digital signal, and converts the analog data received from the analog subscriber line 380 into a digital signal suitable for processing by the digital exchange 300. Taμ7! awPCM
The data is DA converted into analog data and sent to the analog subscriber line 380.

Next, in FIG. 3, 111 in the ES unit 110 is an elastic memory (ESs) for transmission, Di is a data input terminal, DO is a data output terminal, WC is a clock terminal for write clock, and RC is a data input terminal. This is a clock terminal for a read clock. Reference numeral 112 denotes a reception elastic memory (ES1), and the meanings of each terminal Di, Do, WC, and RC are the same as in ESsll.

Reference numeral 121 in the signal processing unit 120 is a deformat circuit, which separates and outputs the transmission data SD and S bit (the S bit will be explained in FIG. 4) from the input universal signal, and also converts the data based on this S bit. A transmission request signal R8 is generated.

122 is a format circuit which adds an F bit (see FIG. 4) and an S bit to the data read out from the ES*112 to create a universal signal. The S bit carries the CD signal.

123 is a timing signal generation circuit that generates write and read clocks synchronized with the operating clock of the digital exchange 300 side.

Reference numeral 124 denotes a gate circuit, which opens when R3 is input, and applies a signal input from the timing signal generation circuit 123 to the 83 section 110.

125 is also a gate circuit which gates the write tally from SAMD by CD.

Reference numeral 130 denotes an interface unit that exchanges data with the SAMD 200 through a V24/35 connection interface.

140 is an analog line signal processing section, and a decoder 141
and Korg 142. The decoder 141 decodes the μmawPCM code transmitted from the digital exchange 300 into analog data. Korg 142 receives μl of analog data transmitted from SAMD200.
Encode into awPCM code.

150 is an interface section, which connects SAM via a 2-wire or 4-wire analog interface (usually 600Ω balanced).
Exchanges data with the D200.

In the SAMD 200, 210 is a terminal on the digital subscriber line side (DTE), and 220 is an analog line (LINE) to which an analog subscriber is connected.

FIG. 4 shows the signal format on the digital subscriber line 330, which is called a (6+2) envelope format.

Six data bits D0 to D, in which data information is set, are arranged between the first F bit and the last S bit. The S bit is a control bit for transmitting R3 and CD. The F bit is a bit for synchronization.

Note that various types of elastic memories known as ESsll and ES1112 or buffer memories having functions equivalent to these can be used.

(b) Description of operation Terminal 350, modem 360, NCU 370, analog subscriber line 380. ALC390, digital exchange 300
, analog signal processing unit 140, LINE 220, etc., data communication on the analog subscriber side is the same as the conventional one, and is not directly related to the configuration and operation of MDPTloo of the present invention. The explanation will be limited to the above-mentioned configuration, and detailed explanation of its operation will be omitted.

In mutual communication between the terminal 310 connected to the digital subscriber line and the digital interface 210 side of the synchronous modem 200, the DTE 310, DAU 320, digital subscriber line 330, DLC 340, and digital exchange 3
Since the operation between 00 and 00 is the same as the conventional one, the operation of MDPTloo in FIG. 3 will be mainly explained below. As mentioned earlier, the connection interface complies with CCITT recommendation V.
24/35.

(b-1) When transmitting data SD from the digital exchange side to the SAMD side, the universal signal is sent from the digital exchange 300 to the MDP
When sent to Tloo, the deformat circuit 121 extracts the transmission data SD and S bit from the input universal signal. Note that the S bit is an R3 signal. The transmission data SD is applied to the input terminal Di of ESsll. The S bit is applied to gate circuit 124 to open it. Furthermore, the T format circuit 121 generates a transmission request signal R3 based on the S bit and applies it to the interface section 130.

The timing signal generation circuit 123 is connected to the digital exchange 3
Transmission timing signal S synchronized with the operation clock on the 00 side
T, is generated and sent to the interface section 130, and
It is applied to the write clock terminal WC of ESsll through the gate circuit 124.

ESsll is a transmission timing signal ST.

The input transmission data SD is written using as a write clock.

The interface unit 130 sends a transmission request signal RS and a transmission timing signal S T t to the SAMD 200 . Then, with the clock ST2 sent from SAMD200, E
Read the transmission data SD stored in Ss 111, and
The transmission data SD is sent to the synchronous modem 200 according to the transmission procedure of No. 24. ESsll is the transmission timing signal S
The transmission data SD written in T+ is clocked STZ
The operation of reading data is well known.

SAMD200 operates with clock ST, but if ST2 is within the synchronization range of transmission timing signal ST sent from MDPTloo, SAMD2QQ is synchronized with ST, and the clock sent to MDPT is also STI.
becomes.

The transmission request signal R3 is transmitted for the minimum required time until the end of transmission according to the communication procedure, and during that period ESs 111
In this case, the data information is read by compensating for the frequency deviation between the digital exchange 300 and the SAMD 200.

(b-2) When transmitting the received data RD from the SAMD side to the digital exchange side The SAMD 200 sends the received data RD to the interface section 130 of MDPTloo according to the communication procedure specified in V24.

The interface unit 130 writes the received data RD into the ESR 112 using the reception timing signal RT sent from the SAMD 200.

Note that RT is gated by the gate circuit 125 by CD, which has the same function as the gate circuit 124.

The timing signal generation circuit 123 of the signal processing section 130 is
ES using the transmission timing signal ST as a read clock
In addition to 1112, the stored received data RD is read out and sent to the formant circuit 122.

The format circuit 122 formats the input received data by
The F and S bits are added to form a universal signal and sent to the digital exchange 300. Note that the S bit is a CD signal.

Although one embodiment of the present invention has been described above, each structure of the present invention is not limited to the structure of this embodiment.

For example, the signal format on a digital subscriber line is
Signal formats other than those shown in FIG. 4 can be used. The connection interface for communication may also be other than V24.

〔Effect of the invention〕

As explained above, according to the present invention, since the MDPTloo equipped with the ES section 111 compensates for the frequency deviation between the operating clocks on the digital exchange 300 side and the SAMD 200 side, the operating clock of the digital exchange 300 and It is possible to perform mutual communication between an analog terminal connected to SAMD 200 and a digital terminal of digital exchange 300, which have different operating clocks.

[Brief explanation of drawings]

Fig. 1: Detailed explanatory diagram of the present invention; Fig. 2: explanatory diagram of the configuration of a communication system using a synchronous modem boolean device according to the present invention; Fig. 3: synchronization of the present invention FIG. 4 is an illustration of the signal format on a digital subscriber line. In FIGS. 1 to 3, 100...Synchronous modem boolean device (MDPT), 1
10... Elastane ink memory section (ES section), 120
. . . signal processing unit, 200 . . . synchronous analog modem (SAMD), 300 . . . digital exchange.

Claims (1)

[Claims] A synchronous modem pool (100) is provided in a digital exchange (300) that accommodates digital lines and analog lines, and enables connection between the digital line and the analog line. 200), a signal processing unit (120) is connected to the route that interfaces with the digital line.
and an elastic memory unit (110), and a clock (S) for reading and writing from the digital exchange side.
1) and a clock (ST_2, RT) for writing and reading from the synchronous modem side, respectively, are made independent.