JPS634740A - Data transmission system - Google Patents

Abstract

PURPOSE:To attain excellent data transmission in the timing corresponding to a digital line by using a carrier converter or a single carrier MODEM so as to transmit a carrier detect signal being a reply signal from a terminal quipment to a HOST computer without intermitting an analog line. CONSTITUTION:A carrier converter 17 (CADP2) has a reception section of a carrier detect signal CD from a TDM 10 and a timing reception section and constitutes a conversion means to send the carrier detect signal CD to the MODEM 5 as a data and a means applying its inverse conversion. In sending a data while interconnecting a digital line and an analog line, the system consists of the HOST computer 1, MODEMs 4, 5-8, TDMs 10, 11, terminal equipments 2, 3 and carrier converters 16,17. Thus, the carrier detect signal is turned on/off without itnermitting the analog line.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a time division multiplexing device (hereinafter referred to as TDM).
9. Concerning a data transmission system that performs data transmission by interconnecting a digital line used using a data modulation/demodulation device (hereinafter referred to as a modem) and an analog line used using a data modulation/demodulation device (hereinafter referred to as a modem). In particular, the present invention relates to a data transmission method suitable for implementation when the HO8T computer is located far from the digital line TDM and therefore must be transmitted using a modem.

[Conventional technology]

Conventionally, an example of a data transmission method in which data transmission is performed by interconnecting this type of digital line and analog line is shown in Section 7.
It is shown and explained in FIG. 8 and FIG.

In Fig. 7, 1 is the HO8T computer, 2.3 is the terminal, 4, 5...8 is the modem, 10.11 is the TDM,
12 is the timing source of the digital line.

13m and 13b are analog lines, and 14 is a digital line.

In FIG. 8, the same symbols as in FIG. 7 indicate corresponding parts, 9 is a modem, and 13c is an analog line.

15 is a DC branch device (DB).

When transmitting data by interconnecting a digital line and an analog line, as shown in FIG. 7, TDMIO and modem 5 are interconnected, and
As shown in the figure, TDMlo and DC branch device (DB) 1
5. This was done using a multi-point configuration in which modems 5 and 8 were interconnected.

Next, the operation of the multi-point data transmission system as shown in FIGS. 7 and 8 will be explained. Note that since FIG. 8 is one of the applications shown in FIG. 7, the explanation will be mainly based on FIG. 7 here.

First, since the digital circuit 14 has the timing fo of the digital circuit timing source 12, the TDMI O, 11 and modems 4, 5 that make up the system
. . . 8 must operate according to this timing in jlE (dependent synchronization method).

Among these, HO3T computer 1 is terminal 2,
Terminal 2 is called from the data in jO (here, it is assumed that this terminal 2 is called by the HOST computer 1). ) sends back a response signal and data.

Then, this HO8T computer 1 receives the response signal when the carrier detect signal CD of the modem 4 is 1ON', and starts receiving data. Note that when the carrier detect signal CD is OFF', it means that no terminal is responding to a call from the HO8T computer 1.

Next, in order to transmit the carrier detect signal CD to this HO8T computer 1, the terminal 2 sends a request to the modem 7, request-to-send R8-modem 6's carrier detect signal CL)"ON"-Tr)Mll request. - Two send P, S"ON" - TDMIO carrier detect signal CD "ON" - Modem 5 request - Two send R8'"ON" - Modem 4 carrier detect signal CD "ON".

[Problem that the invention seeks to solve]

In the conventional data transmission system described above, turning the carrier detect signal CD of the modem 4 "ON"/OFF means cutting off the analog line 13m (R8 "OFF'F" of the modem 5).
"L, CD of modem 4"OF'F', then modem 5 (
DBS "ON" L, % DE A4 CD "ON"). Then, when the analog line 13a is turned on and off, the timing dependent destination of the modem 4 is the digital line 14 when the carrier detect signal CD is "ON".
The timing f of the timing source 12.

is dependent on the “O” of the carrier detect signal CD.
FF''' operates at the timing when modem 4 free-runs (also called self-running), and the section between modem 4 and 5 becomes independent synchronization.As a system, the timing generation of the digital line It must be a dependent synchronization scheme dependent on the timing fo of the source 12.

However, modem 4's carrier detect signal CD's
OFF”, it becomes independent synchronization, so HO8T
There is a problem in that data from the computer 1 causes data slips and data dropouts between the modem 5 and TDMIO, making it impossible to transmit data correctly and resulting in system down.

As an example, the time chart of FIG. 7 is shown in FIG. In the time chart shown in FIG. 9, (,
) is a request-to-send R from terminal 2 to modem 7
(b) is the clear-to-send C8 from modem 7 to terminal 2. (C) is the carrier of modem 7. (d) is the carrier detect signal CD of modem 6 and the request of TDMll. Two send R8, (e) is the reception timing RT of the modem 6 and the transmission timing S T I of TDMli, (f) is the reception data RD of the modem 6
and TDMil transmission data SD, (g) is TDMIO carrier detect signal CD and modem 5 request -
Two send R3, (h) is the reception timing RT of TDM10 and the transmission timing ST+ of modem 5, (i) is the carrier detect signal CD of modem 4, (j) is the modem 4
reception timing RT and modem 4 transmission timing ST
2, (b) is received data IID from modem 4 to HO8T computer 1, (4 is request-to-send R8 of modem 4, (m) is sent data SD from HO8T computer 1 to modem 4, (n) is Modem 5 carrier detect signal CD and TDMlo request-to-send R8° (0) is modem 5 reception timing RT
and TDMiQ transmission timing ST1. (P) is the received data RD of modem 5 and the transmitted data SD of TDMIO, (
q) shows data on the digital line 14.

9 (d), (g) and (i) K in K means from terminal 2 and from terminal 3, respectively; 1. is the timing due to free run of modem 6, t
2 is the timing f of the timing generation source 12 of the digital line. DT+ is the valid error data from terminal 2 (FIG. 9 (for (1)).

DT2 is valid error data from terminal 3 (Fig. 9 (q))
). Then, t3 is the timing of 7 reruns of modem 4, DT3 is the call data to terminal 2, DT4 is the call data to terminal 3, DTs is the call data to terminal 2 (free run timing of modem 4), and DTs is the call data to terminal 2 (free run timing of modem 4). Call data to terminal 3 (modem 4 free run timing), DT 5a if data error slip, etc., DT6. is a data error slip, etc.

As can be understood from the time chart shown in FIG. 9, the data from the terminal 2 to the HO8T computer 1 is
Request-to-send R8 of modem 5 shown in figure (g)
'0N10FF' of modem 4 shown in Figure 9(i)
The carrier detect signal CD of "ON10 F F" is turned on.Then, this carrier detect signal CD of "ON10 F F"
"The time is the reception timing P of the modem 4 shown in FIG. 9(j)K.
, T and the transmission timing ST2 are the timing f of the timing generation source 12 of the digital line. However, when the carrier detect signal CD is "OFF", the modem 40 free run frequency (also known as free run frequency a: fMl
) will work.

Since the call data to the terminals 2 and 3 is transmitted at this transmission timing STz, the system uses the timing fo of the timing source 12 of the digital line.
Where it is necessary to operate in accordance with the above-mentioned free-running frequency f, the data according to the timing of the above-mentioned free-running frequency f is transmitted to the received data RD of the modem 5 and the transmitted data S to the TDMlo shown in FIG. 9 φ).
It is transmitted as D.

Therefore, the data based on the timing of the free-running frequency fws is the timing f of the timing generation source 12 of the digital line. 9 ((1)) is transmitted on the digital line 14 shown in FIG. The terminal is HO8T
There was a problem in that correct data could not be transmitted to the computer 1 and the online system would stop.

[Means for solving problems]

The data transmission method according to the present invention is a data transmission method in which a digital line used using TD~1 and an analog line used using a modem are interconnected to perform data transmission, and the carrier from the TDM is a detect signal receiving section, a timing receiving section, a converting means for transmitting the carrier detect signal as data to the modem, and a means for performing inverse conversion; This allows for good communication without causing dropouts or the like.

7E1 A data transmission system according to another aspect of the present invention includes a conversion means for receiving a carrier detect signal from the TDM, receiving timing, and transmitting the carrier detect signal as data, and an inverse conversion thereof. It is designed to include means 2 for carrying out the procedure.

[Effect]

In the present invention, the carrier detect signal is turned on and off without interrupting the analog circuit.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 are block diagrams showing an embodiment of a data transmission system according to the present invention.

In FIG. 1, the same numbers as in FIG. 7 indicate corresponding parts, and 16.17 is a carrier conversion device
, CADP2), and this carrier conversion device 17 (
CADP2) receives the carrier detect signal CD from TDMIO f! It has a converter section and a timing receiver section, and constitutes converting means for transmitting the carrier detect signal CD to the modem 5 as data and means for performing the inverse conversion. FIG. 1 shows a HO8T computer 1 and a modem 4.5-.
・8 and TDbxl 0, 11 and terminal 2
, 3 and carrier conversion devices 16 and 17.

In Fig. 2, the same reference numerals as in Figs. 1 and 8 indicate corresponding parts, and this Fig. 2 shows the HO8T computer 1.
and modems 4, 5, φ, 9, TDMlo, 11, terminals 2, 3, DC branching device 15, and carrier converting devices 16, 17.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to the time chart shown in FIG.

Since FIG. 2 is one of the applications shown in FIG. 1, the explanation will be made with reference to FIG. 1 and FIG. 3, which is an example of the time chart of FIG. 1.

In FIG. 3, (&) indicates a request-to-send R8 from the terminal 2 to the modem 7.

(b) is clear-to-send C from modem 7 to terminal 2
3. (c) is the carrier of modem 7, (d) is the carrier detect signal CD of modem 6 and request-to-send R8 of TDMi 1, (e) is the reception timing RT of modem 6, ! : TDMll transmission timing ST+,
(f) is the received data RD of modem 6 and the transmitted data SD of TDMll, ω) is the carrier detect signal CD of TDMlo and the carrier detect signal CD of CADP217
l1 can) is TDMIO reception timing RT and CADP
217 reception timing lζT, (i) is CADP21
7's carrier detect signal CD2 and modem 5's request-to-send R8, (j) is modem 4's carrier detect signal CD and CADPI 16's carrier detect signal CD, (2) is modem 4's reception timing RT, ! : CADPI 16 reception timing RT
and CADPI 16 transmission timing ST2. (t
) is CADP+16 carrier detect signal CD2,
(m) is CADP.

161J et al. HO8'r reception (Et data, <n) to HO8'r computer 1 is from HO5T computer 1 to CADPI
Send data SD to 16 and CAIJP+ Send data SD from 16 to modem 4, '(o) is request-to-send R3 of modem 4, (p) is carrier detect signal CD of modem 5 and Yayaria detect of CADP217 Signal CD and TDMI O glue clear-to-send R8, (q) is modem 5 reception timing R'r and C
Reception timing RT of ADP 217 and transmission timing ST+ of TDMlo, (r) is reception data I'LD of modem 5 and reception data Li) of CADP 217, and transmission data SD of TDMiQ, (s) is data on digital circuit 14 This is what is shown.

3 (d), (g), and (t) respectively mean from the terminal 2 and from the terminal 3, and t4 is the timing fo of the timing source 12 of the digital line. t5 is the timing due to free run of modem 6, DT7 is valid data from terminal 2, DTs is valid data from terminal 3, DT9
is the call data to terminal 2, DT+.

is the call data to terminal 3, DTII is the call data to terminal 2 (timing fo), DT, 2
is the call data to terminal 3 (timing fo ),
DT lr & is the data (correct data) at the timing of fo, and the data (correct data) at the timing of DT+2JL'I'if o.

If, ll08T It is assumed that computer 1 and terminal 2.3 perform data transmission. As previously mentioned, this data transmission system must operate in a dependent synchronization manner dependent on the timing f of the timing source 12 of the digital line 14.

Tsukini, ll08T computer i & [end 2, 3 is in a state where data is not being transmitted (request-to-send R8 "ON"), and the data in this state is
First, terminal 2 and then terminal 3 are called to perform data transmission. Then, in order to send data back to the HO8T computer 1, the terminal 2 that was called first sends a request to the modem 7. ”
, TDMII request-two send R8″ON
” (See FIG. 3(d)) - TDMiQ carrier detect signal CD “ON”.

CADP217 carrier detect signal CD'''ON
(See Figure 3 (g)) - CADP217 always carrier detect signal CD 2 "ON", modem 5 always request-to-send R8 "ON" (See Figure 3 (1))
-Modem 4 constant carrier detect signal CD'''ON''
.

CADP116 constant carrier detect signal CD”ON
” (see FIG. 3 (j)) - carrier detect signal CD2 of CADPll 6 “ON” (see FIG. 3 (4)), a response signal is sent.
Even though the carrier detect signal CD from the CADP+ 16 is turned on and off for the 8T computer 1, the timing generation source 1 of the digital line
The reception timing RT synchronized with the timing fG of 2 and the transmission (i timing 5T2 (see FIG. 3 (2)) are supplied.

In this way, the transmission timing 5T21' is synchronized with the timing fo of the timing source 12 of the digital line.Since the calling data is sent from the computer 1 to the terminal 2.3, the reception data RD, CADPz 17 from the modem 5 is The received data RD from the TDMlo, the transmission data SD to the TDMlo, and the data synchronized with the timing f0 of the timing generation source 12 of the digital line are transmitted. No data slip occurs between the lines 14, and good data transmission can be performed.

As described above, the invention according to the embodiment shown in FIG. 1 and FIG. Carrier detect signal CDf, which is a response signal to the computer, can be transferred without interruption through the analog line, and good data transmission can be achieved by timing dependent on the digital line.

FIGS. 4 and 5 are block diagrams showing other embodiments of the present invention.

In FIG. 4, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. 18.19 is a single carrier modem (C modem 1, C modem 2), and this single carrier modem fi19 (c-F: dem 2) is a TDM
It constitutes conversion means for receiving the carrier detect signal CD from the IO, receiving the carrier detect signal CD at all timings, and transmitting the carrier detect signal CD as data, and means for performing the inverse conversion. FIG. 4 shows HO3T communication 1 and modem 6.
7.8 and TDMl 0 , 11 and terminal 2
゜3 and a single carriers demodulator ff18.19jυ.

In FIG. 5, the same parts as those in FIG. 4 and FIG. 2 are given the same reference numerals, and explanations thereof will be omitted. This figure 5 shows the HO8T computer 1, modems 6.7...9 and TDMl.
0 and 11, terminals 2 and 3, a DC branch membrane 15, and single carrier modulation/demodulation devices 18 and 19.

Next, the operation of the embodiment shown in FIG. 4 will be explained with reference to the time chart shown in FIG. In addition.

Since FIG. 5 is an application of FIG. 4, the explanation will be made with reference to FIG. 4 and FIG. 6, which is an example of the time chart of FIG. 4.

Figure 6 is a time chart for explaining the operation of Figure 4.
(B) shows the request-to-send R8 from terminal 2 to modem 7, (b) shows clear-to-send C8 from modem 7 to modem 2, (C) shows the carrier of modem I, (d) is the modem 6 carrier detect signal CD and TDMil request-to-send R8, (e
) is the reception timing RT of modem 6 and the transmission timing ST+ of TDMll, (f) is the reception data RD of modem 6
and TDMll transmission data, 1g) is the carrier detect signal CD of TDMi Q and the request-to-send R8 of C modem t19, ()I) is the reception timing RT of TDM10 and the transmission timing ST of C modem 219,
, (i) is the internal request-to-send R8 of the C modem 219, (j) is the internal carrier detect signal CD of the C modem +18, and ■ is the reception timing R of the C modem 118.
T and transmission timing ST, (4 is C modem) 1
8 to the HO8T computer 1, (m) is the received data sD from the C modem 118 to the HO8T computer 1, (n) is the transmitted data SD from the HO8T computer 1 to the C modem s18.
, (o) is C modem] Request-to-send R8 of 18, (p) is request-to-send R5 of carrier detect signal CD of C modem 219 and TDMlo,
(q) is C modem] 19 reception timing RT and TDM
l 0 transmission timing ST+, (r) is C modem 21
9 received data RD l! :TDMl 0 tD transmission data SD, (3) shows the data on the digital line 14.

6(d), (2) and V) respectively mean from the terminal 2 and from the terminal 3, t4 is the timing dependent on the timing fo of the timing source 12 of the digital line, t5 is timing due to free run of modem 6, DT is valid data from terminal 2, DTs is valid data from terminal 3, and DT is call data to terminal 2.

DT, , is call data to terminal 3, DT is terminal 2
Call data to (timing f.).

DT, , is the call data to terminal 3 (timing fo
), DT,1& is the data at the timing of fG (correct data), and DTs2a is the data at the timing of fo (
correct data).

First, it is assumed that the HO8T computer 1 and the terminals 2 and 3 perform data transmission. As mentioned above, this data transmission system must operate in a dependent synchronization manner dependent on the timing f0 of the timing source 12 of the digital circuit a14.

Next, the HO8T computer 1 is in a state where it is unable to transmit data to the terminal 2.3 (request-to-send R8'"ON"), and the data is transmitted first to the terminal 2 and then to the terminal 2.3. 3 and performs data transmission. Then, the first called terminal 2 sends the Q-to-Send RS "ON" to the modem 7 in order to send the data back to the HOST computer 1 (see Figure 6 (a)).
- Modem 6 carrier detect signal CD "ON", T
DMll request - Two send R8 "ON" (see Figure 6 (d)) - TDMIO carrier detect signal CD "ON", C modem 219 internal request - Two send R8 always "ON" (Figure 6 (g)) , (i)
) - Internal carrier detect signal CD of C modem t18 always "ON" (see Figure 6 ( )) - C modem tl
The carrier detect signal CD "ON" from B to HO8T computer 1 (see Figure 6 Cl)),
A response signal is sent. At this time, even though the carrier detect signal CD from the C modem +18 is turned ON and OFF to the HO3T computer 1, the reception timing RT is synchronized with the timing fo of the timing generation source 12 of the digital line.

The transmission timing 5T2 (see FIG. 6 (ω)) is supplied.

In this way, with the transmission timing STz synchronized with the timing fo of the timing generation source 12 of the digital line,
9I (Since the call data is being sent from the O8T computer 1 to the terminal 2.3, the received data RD from the C modem 219, the transmitted data SD to TDMIO, and the timing f of the timing source 12 of the digital line.
Since data synchronized with o is transmitted, the conventional 7th
Modem 5, TDMIO, and digital line 14 in the diagram
Good data transmission can be performed without data slips occurring between the two.

As described above, the invention according to the embodiment shown in FIGS. 4 and 5 can transmit data from a terminal to H
A carrier detect signal (CD), which is a response signal to the O8T computer, can be transferred without interrupting the analog line, and excellent data transmission can be achieved by timing dependent on the digital line.

〔Effect of the invention〕

As explained above, according to the present invention, in data transmission in a system configuration in which an analog line and a digital line are interconnected, a carrier conversion device or a single carrier modulation/demodulation device is used.
The carrier detect signal (CD), which is a response signal to the O8T computer, can be transferred without interrupting the analog line, and the timing dependent on the digital line allows for better data transmission, so the practical effect is It is extremely large.

[Brief explanation of drawings]

1 and 2 are block diagrams showing an embodiment of the data transmission system according to the present invention, FIG. 3 is a time chart for explaining the operation of FIG. 1, and FIGS. 6 is a time chart for explaining the operation of FIG. 4, FIGS. 7 and 8 are block diagrams showing examples of conventional data transmission systems, and FIG. 9 is a diagram showing the example of the conventional data transmission method. It is a time chart for explaining the operation. 5... Data modulation/demodulation device, 10.11... Time division multiplexing device, 13a to 13C... Analog line,
14...Digital line, 16°17...Carrier conversion device, ia, iq...Single carrier modulation/demodulation device.

Claims (2)

[Claims] (1) In a data transmission system that performs data transmission by interconnecting a digital line used using a time division multiplexing device and an analog line used using a data modulation/demodulation device, from the time division multiplexing device a carrier detect signal receiving section; a timing receiving section; converting means for transmitting the carrier detect signal as data to the data modulation/demodulation device; and means for performing inverse conversion of the carrier detect signal; A data transmission method that is characterized by being able to perform good communication without causing slips, dropouts, etc. (2) In a data transmission system that performs data transmission by interconnecting a digital line used using a time division multiplexing device and an analog line used using a data modulation/demodulation device, from the time division multiplexing device and a converting means for receiving a carrier detect signal and transmitting the carrier detect signal as data by receiving the timing, and a means for inversely converting the carrier detect signal, without causing slips or omissions of the data. A data transmission method characterized by being able to perform good communication.