JPH01282958A - Communications system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] TECHNICAL FIELD The present invention relates to communication systems.

[Prior Art] In recent years, attempts have been made to connect a facsimile machine to a key telephone system, for example, as a communication system of this type.

[Problem to be solved by the invention] The dedicated telephone of the key telephone system is used as a facsimile machine and 4
When connected via a line and used as a facsimile adapter, it is desirable to respond to a telephone reservation for facsimile communication by going off-hook with the handset of the dedicated telephone. Therefore, there is a need for a means to know that it is a telephone reservation without knowing the contents of the facsimile communication procedure. The determination can be made by synchronizing the off-hook and on-hook states of the telephone and detecting the DC loop with the DC loop detection circuit 2 while the DC loop detection circuit 1 is still detecting the DC loop. This is because the above state means that the facsimile machine has connected the 1-line terminal and the telephone terminal without breaking the DC loop, and it can be determined that the call path has been switched from the modem to the telephone due to telephone reservation. This is because that. However, in the case of telephone reservations, before the facsimile machine connects the line terminal and telephone terminal, a current is passed through the telephone terminal in order to determine whether the telephone that is supposed to be connected to the telephone terminal is off-hook. , this current is detected by the DC loop detection circuit 2,
If it is determined as if the facsimile line terminal and telephone terminal were connected, and the call line is switched from the facsimile side to the call circuit side based on this judgment, the call line will be switched before the facsimile call procedure is completed. A facsimile communication error occurs.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a first connection means for connecting to a data communication terminal, and a second connection means for connecting to a communication means of the data communication terminal. , a first DC loop detection means for detecting that a DC loop is formed on the line connected by the first connection means;
DC loop forming means for forming a DC loop on a line connected by the connecting means; and second DC loop detecting means for detecting that a DC loop is formed on the line connected by the second connecting means. , means for switching a telephone line connected to the main device between a telephone connected to the telephone circuit and the data communication terminal, and switching the telephone line switching means to the data communication terminal side to perform data communication. means for synchronizing DC loop formation and DC loop disconnection of the DC loop forming means with off-hook and on-hook of the handset of the telephone in a state in which the DC loop is detected by the first DC loop detection means, means for fixing the DC loop formed in the DC loop forming circuit until at least a short time after the second DC loop detection means first detects a DC loop, the switching means for the communication line is switched to the communication circuit side; Second
Either a certain period of time passes after the DC loop detection means first detects a DC loop, or the second DC loop detection means stops detecting a DC loop again after first detecting a DC loop, and then detects a DC loop again. A configuration is adopted in which means is provided for switching the communication line switching means to the communication circuit side when the communication line is detected.

[Function] According to the above configuration, it is possible to switch the call line from the data communication terminal side to the call circuit side after the data communication procedure is completed, and it is possible to respond to the telephone reservation without causing a data communication error. It becomes possible.

[Examples] The present invention will be described in detail below based on examples shown in the drawings.

FIG. 1 is a system configuration diagram of a key telephone system. In FIG. 1, reference numeral 1 indicates a telephone line, which is connected to the main unit of the key telephone system, reference numeral 2. The main device of the key telephone system is connected to a dedicated telephone with a facsimile adapter function indicated by reference numeral 5 through four wires, two of which are used as telephone line 3 for telephone calls, and the other two wires are , is used as a control line 4 used to control a dedicated telephone. The dedicated telephone numbered 5 is connected to the facsimile numbered 8 with 4 wires, of which 2! 1 is used as a telephone line 6 connected to a line terminal 9 of the facsimile, and the other two lines are used as a DC loop forming line 7 connected to a telephone terminal 10 of the facsimile.

FIG. 2 is a block diagram showing the configuration of a dedicated telephone with a facsimile adapter function, which is designated by the reference numeral 5 in FIG.

The telephone line 3 connected to the main device is connected to two relays (15a, 15b) which are synchronously controlled by a control circuit 19.
), hook switch 11 and DC loop detection circuit 1
The connection can be switched between (16) and (16). When used as a normal telephone, the relay 15a connects the telephone line &i3, which is connected to the main device, to the hook switch 11, and when the hook switch 11 is closed, the relay 15a connects the handset You can make calls using At this time, the relay 15b connects the DC power supply circuit 14 to the telephone line 6 to the facsimile, thereby supplying power to the facsimile. When performing facsimile communication, the control circuit 19 switches the relays (15a, 15b) at the same time to connect the telephone line 3 from the main device and the telephone line 6 to the facsimile. DC loop detection circuit 1 (
16) is a circuit for detecting whether a DC loop is formed on the telephone line 6 to the facsimile, and transmits this information to the control circuit 19. Also, hook switch 1
1 is also transmitted to the control circuit 19.

Forms a DC loop connected to the facsimile telephone terminal lO! i7 is connected to the DC loop forming circuit 17 via the DC loop detection circuit 2 (1B). The DC loop forming circuit 17 is a circuit that simulates the hook switch operation of a telephone attached to a facsimile, and forms or breaks a DC loop under the control of the control circuit 19.

The DC loop detection circuit 2 (18) is a circuit that detects whether or not a DC loop is formed on the DC loop forming line 7, and transmits this information to the control circuit 19.

A control line 4 from the main device is connected to a main device interface 20, and its information is transmitted to a control circuit 19.

Furthermore, keys 21 are keys such as dial keys, one-touch dial keys, function keys, etc., and the information on the pressing of these keys is transmitted by the control circuit 19.
It is sent to the main device via the main device interface 20.

FIG. 3 is a block diagram of a numerical facsimile circuit configuration. Line terminal 9 to which the telephone line 6 is connected
There are two relays (24a) controlled by the control circuit 27.

24b) to the telephone terminal IO. When a normal facsimile attached telephone is connected to the telephone terminal 10, a direct current loop is formed in the direct current loop forming line 7 by off-hooking the facsimile attached telephone, and a call can be made through the telephone line 6. When performing facsimile communication, the control circuit 27 forms a DC loop in the DC loop forming circuit 22, and the relay 24
The DC loop detection circuit 31 that performs communication by switching the terminal a to the modem 25 side is a circuit that detects that a DC loop is formed in the DC loop forming line 7, and the information is transmitted to the control circuit 27. When a telephone reservation is made in the facsimile communication procedure, the control circuit 27 controls the sound source 32.
is controlled, and while emitting a ring tone from the speaker 33, the relay 24b is switched to the DC power supply circuit 28 side, current is supplied to the DC loop forming line 7, and the off-hook of the telephone attached to the facsimile is detected by the DC loop detection circuit 31. wait for. When the operator goes off-hook with the telephone attached to the facsimile, the control circuit 27 transmits the off-hook information to the other party's facsimile, and then sends the two relays (24a
, 24b) to connect the telephone line 6 and the DC loop forming line 7, thereby making it possible to make a telephone call using the telephone attached to the facsimile. At this time, the DC loop of the DC loop forming circuit 22 is disconnected, and the line is disconnected by turning on the facsimile attached telephone. Further, the dialing circuit 23 is a circuit that performs dialing in response to a signal from the control circuit 27, and the keys 26 include a start key, stop key, numeric keypad, one-touch dial key, function key, etc. The 0 figure reading section 29 is a circuit that performs dialing based on a signal from the control circuit 27. The graphic information is read and transmitted to the control circuit 27, and the graphic output section 30 outputs a graphic based on the graphic information transmitted from the control circuit 27. Next, the operation in the above configuration will be explained.

FIG. 4 shows a control procedure for a dedicated telephone for responding to a telephone reservation. The procedure shown in FIG. 4 is as follows:
9 is stored in the ROM 19a.

Step Sl in FIG. 4 is executed by resetting the control circuit 19, or by switching the relay 15a to the hook switch 11 side, switching the relay 15b to the DC loop power supply circuit 14 side, and cutting off the DC loop of the DC loop forming circuit 17. do. In step S2, the state of the hook switch 11 is monitored, and when it becomes off-hook, an off-hook code is sent to the main device in steps S3 and S4, a DC loop is formed by the DC loop forming circuit 17, and step S5. S6.3
We are in the loop of 7. In step S5, normal telephone function processing is executed, and when on-hook is detected in step S6, the DC loop of the DC loop forming circuit 17 is disconnected in step S21, and an on-hook code is transmitted to the main device in step S22. Returning to step S2 for monitoring the hook switch. In step S6, if it remains off-hook, in step S7, the DC loop detection circuit 2 (18)
It is determined whether or not a DC loop is detected, and if a DC loop is detected, the loop of steps S5, S6, and S7 is repeated.

Step S7 is for determining whether the relay 24a of the facsimile is switched to the modem side (that is, whether the facsimile is conducting facsimile communication), and if the facsimile is not conducting facsimile communication, one call is made. Since the line 6 is connected to the DC loop forming line 7, the DC loop detection circuit 2 (1B) detects a DC loop. Now, if the relay 24a switches to the modem side and performs facsimile communication, the DC loop detection circuit 2 will not detect a DC loop, so in step S8, the two relays (15a, 15b) are switched and the communication line 3 connect to the facsimile, step S9,
S10. The process enters the loop of S11. In step S9, the cutting and forming of the DC loop of the DC loop forming circuit 17 is synchronized with the opening and closing of the hook switch 11, thereby simulating the operation of the hook switch of the telephone attached to the facsimile. During facsimile communication, step S9.5I
Repeat the O1Sll loop. This is because at the time of facsimile communication, the facsimile forms a DC loop in the DC loop forming circuit 22, and the relay 24a
This is because the DC loop detection circuit 1 (16) detects the DC loop and the DC loop detection circuit 2 (18) does not detect the DC loop because the modem side is switched to the modem side.

Now, there are two ways to end facsimile communication. One is that the fax machine disconnects the line,
The other is when the facsimile connects to the telephone attached to the facsimile without disconnecting the line.
This is the case in response to a so-called telephone reservation, which causes an operator to make a call. In the former case, since the facsimile machine disconnects the line, it can be determined that the facsimile communication has ended when the DC loop detection circuit 1 (16) no longer detects the DC loop. Therefore, if the DC loop detection circuit 1 (16) no longer detects a DC loop in step SIO, the two relays (15a, 15b) are activated in step S20.
) to connect 1 call line 3 to hook switch ll side, execute S21 and S22, and connect hook switch 1
Return to the monitoring state of 1. In the latter case, the facsimile machine emits a ringing tone from the speaker 33 and switches the relay 24b to the DC power supply circuit side without disconnecting the DC loop of the DC loop forming circuit 22 to form a DC loop on the DC loop forming line 7. The DC loop detection circuit 31
to monitor. Therefore, when the handset of the dedicated telephone is taken off-hook in response to a facsimile call, the DC loop forming circuit 17 forms a DC loop, so the DC loop detection circuit 2 (18) detects the DC loop. Of course, at this time, the DC loop detection circuit 1 (16) continues to detect the DC loop. Therefore, step S
When the DC loop detection circuit 2 (18) detects a DC loop in step S12, a timer is started in step S12, the DC loop formation in the DC loop forming circuit 17 is fixed in step S13, and step S14. The process enters a loop of S15 and S16. The reason why the DC loop formation is fixed in step S13 is to prevent the DC loop detection circuit 2 (18) from malfunctioning due to disconnection of the hook switch 11 or the like.

Now, when the dedicated telephone goes off-hook, the facsimile machine detects a DC loop with the DC loop detection circuit 31.
After determining that the operator's handset is off-hook, the DC power supply circuit 28 interrupts the supply of current, and after transmitting a facsimile communication command indicating the operator's response to the other party's facsimile, the relay (24a.

24b) to connect the telephone line 6 and the DC loop forming line 7. Therefore, the DC loop detection circuit 2 (18) of the dedicated telephone is the DC power supply circuit 28 of the facsimile.
Disconnection of the DC loop is detected once when the switch is off, and then the relay (24a, 24b) is switched again.
Detect DC loop. Therefore, steps S14 and S1
5. In the loop of S16, when the DC loop detection circuit 2 (18) detects the disconnection of the DC loop in step S17, it enters the loop of steps S17, S18, and S19, and in step S19, the DC loop detection circuit 2 (18) again detects the disconnection of the DC loop. If a DC loop is detected, the relay (15
a, 15b) to enable a telephone conversation using the handset 13, and the loop enters the conversation state of the dedicated telephone in steps S5, S6, and S7. Also, step S1
4. The monitoring of the DC loop detection circuit 1 (16) in S17 is to determine whether the facsimile line has been disconnected due to sudden power-off of the facsimile machine, etc. If the line is disconnected, step S20, After executing S21 and S22, the process returns to step S2 for monitoring the hook switch 11. Steps S15, S1
8, the timer set in step S12 is monitored, and if it times out, the relay (15a,
15b) and step S5. The loop returns to the talking state of S6 and S7. The time for this timeout is set to a time sufficient for the facsimile to send a command indicating the operator's response to the facsimile so as not to interrupt the facsimile communication procedure. In particular, if the facsimile machine switches the relays (24a, 24b) without turning off the DC power supply circuit 28, the control procedure in FIG.
15. Since the loop of S16 is repeated, this timeout mechanism becomes effective.

In the above embodiments, a facsimile machine is used as an example of the data communication terminal, but instead of the facsimile machine, a teletex, a word processor (with communication function), or a personal computer may be used.

[Effects of the Invention] As is clear from the above description, according to the present invention, after the data communication procedure is completed, the call line is switched from the data communication terminal side to the call circuit side, and the call reservation can be made without causing a data communication error. It has the excellent effect of making it possible to respond to

[Brief explanation of the drawing]

Figure 1 is a system diagram of the key telephone system, Figure 2 is a block diagram of the dedicated telephone configuration, Figure 3 is a block diagram of the facsimile circuit configuration, and Figure 4 shows the control procedure of the control circuit in Figure 2. It is a flowchart figure. 3...Telephone line 4...Control line 5...Dedicated telephone 6...Telephone line 7...DC loop forming line 8...Facsimile 9...Line terminal 10...Telephone terminal 11 ... Hook switch 12 ... Call circuit 13 ... Handset 14 ... DC power supply circuit 15 ... Relay 16 ... DC loop detection circuit 17 - ... DC loop forming circuit 18 - ... DC Loop detection circuit 2 19... Control circuit 22... DC loop forming circuit 24... Relay 25... Modem 27... Control circuit 28... DC power supply circuit 31-... DC loop detection circuit

Claims (2)

[Claims] (1) a first connection means that connects to a data communication terminal; a second connection means that connects to a communication means of the data communication terminal;
a first DC loop detection means for detecting that a DC loop is formed on the line connected by the first connection means; and a DC loop for forming a DC loop on the line connected by the second connection means. forming means, a second DC loop detecting means for detecting that a DC loop is formed on the line connected by the second connecting means, and a telephone set that connects the telephone line connected to the main device to the telephone circuit. and switching means for switching between the data communication terminal and the data communication terminal, and switching the telephone line switching means to the data communication terminal side,
When data communication is being performed, means for synchronizing DC loop formation and DC loop disconnection of the DC loop forming means with off-hook and on-hook of the handset of the telephone, and the first DC loop detection means detect a DC loop. and a means for switching the communication line switching means to the communication circuit side after a predetermined period of time has elapsed after the second DC loop detection means first detects the DC loop, and disconnecting the data communication procedure. A communication system characterized by responding to telephone reservations without any reservations. (2) While the first DC loop detection means is detecting a DC loop, the second DC loop detection means first detects a DC loop, and then the communication line switching means is switched to the communication circuit side at least for a short period of time. means for fixing the DC loop while being formed by the DC loop forming means until switching;
A communication system comprising means for switching the communication line switching means to the communication circuit side when the second DC loop detection means no longer detects a DC loop and detects a DC loop again.