JPS6346858A - Line switching device - Google Patents

Abstract

PURPOSE:To connect a direct-coupled circuit to a terminal circuit on the same condition as a switching circuit by providing a circuit switching device with a means or the like which transmits and receives a signal generated as prescribed in the direct-coupled circuit. CONSTITUTION:When a terminal line 52 is connected to a direct-coupled line 51 by a switching circuit 13 of the circuit switching device, a signal transmitting and receiving means 14 of the line switching device receives a call signal, a response signal, and a closing signal different in frequency and discriminates these signals in accordance with frequencies. A call signal transmitting means 17, a DC loop detecting means or the like which controls DC loop closing are controlled by a control means 18 based on discrimination results, and thus, the direct-coupled circuit is connected to the communication terminal equipment on the same condition as the switching circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a line switching device for connecting one communication terminal device to one of a plurality of communication lines.

[Common technology]

A communication terminal device connected to an exchange has a ringing signal detection circuit that detects a ringing signal received when a call is received, and a DC loop closing circuit that closes a DC loop as a closing means to notify the exchange that it is in use. When the calling signal detecting circuit detects a calling signal from and responds, the DC loop closing circuit closes the DC loop. Furthermore, the communication terminal device closes the DC loop when the line is in use. (For example, Article 9 of Ministry of Posts and Telecommunications Ordinance No. 31) [Prior Art] Conventionally, a line switching device connected to this type of terminal device has a DC loop formed by a calling signal detection circuit and a DC loop closing circuit in the communication terminal device. Each of the two switched lines has a DC loop detection circuit for detection. When the discharge signal detection circuit detects a calling signal from the exchange, the line switching device connects and calls the communication terminal device to the line on which the calling signal has arrived, and the DC loop detection circuit detects a response from the communication terminal device. Further, when a communication terminal device forms a DC loop, the DC loop detection circuit of the line switching device detects this DC loop, identifies whether the line is in use, and prohibits line switching operation.

[Problem that the invention seeks to solve]

The conventional line switching device described above has a ringing signal detection circuit for each line to be switched, and switches the line by detecting the ringing signal from the exchange, so even when interconnected by direct connection using the line switching device Must be connected via an exchange. Therefore, when a direct connection line that is not connected to an exchange, such as a private branch line, is used, there is a problem in that it is not possible to send or receive a calling signal, and switching operations cannot be performed.

An object of the present invention is to provide a line switching device that solves the above problems.

[Means for solving problems]

The line switching device of the present invention accommodates and connects a terminal line connected to a communication terminal device on one side and a plurality of various lines connecting to another communication terminal device on the other side, and switches the terminal line to one of the various lines. The line switching device to be connected is provided with a direct connection line that directly connects the line switching device as various lines, and has a signal transmitting/receiving means that is connected to the direct connection line and sends and receives signals using a predetermined signal format.

Further, one specific means is that the signal transmitting/receiving means has a generating circuit that generates the frequency assigned to the signal, and an identification circuit that identifies the frequency received from the direct connection line.

〔Example〕

Next, the line switching device of the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the connections of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIGS.
The figures up to the drawings are flowcharts showing an example of the main operation procedure of the present invention.

In FIG. 1, the line switching device is connected to another line switching device 1 by a direct line 51, a communication terminal device 2 by a terminal line 52, and an exchange 3 by a switching line 53. connects the terminal line 52 to either the direct line 51 or the switched line 53.

FIG. 2 is a functional block diagram showing an example of details of the line switching device 1 shown in FIG. 1. In FIG. 2, a calling signal detection circuit 11 and a DC loop detection circuit 12 are connected to the switched line 53 as in the conventional case, and the DC loop detection circuit 12 is connected to a terminal port 11152 via a switching circuit 13. The direct connection line 51 is connected to the signal transmitting/receiving means 14. Trance 15. DC loop detection means 16. and is connected to the terminal line 52 via the switching circuit 13. A calling signal sending means 17 is connected to the DC loop detecting means 16, and a control means 18 is provided to control the functions of the line switching device 1. Calling signal detection circuit 11
detects a paging signal received from exchange 3 (shown in FIG. 1) via switched line 53. DC loop detection circuit 12
is the terminal mouth! Communication terminal device 2 (
1) is detected, and this DC loop is directly connected to the exchange line 53. The switching circuit 13 switches and connects the terminal line 52 to the exchange line 53 or the direct connection line 51. The signal transmitting/receiving means 14 transmits and receives at least a calling signal, a response signal, and a blocking signal via the direct connection line 51. The transformer 15 interrupts the direct current circuit connection between the direct connection line 51 and the terminal circuit 52. The DC loop detection means 16 detects a DC loop formed by the communication terminal device 2 via the terminal line 52.

The calling signal sending means 17 sends out a calling signal to the terminal line 52 via the DC loop detecting means 16.

Next, an example of the main operating procedure of the present invention will be described with reference to FIGS. 3 to 5 together with FIGS. 1 and 2.

FIG. 3 is a flowchart showing an example of the main operation procedure of the line switching device when the communication terminal device 2 is started to be used or designated to be blocked. The communication terminal device 2 forms a DC loop to indicate that it is in use and uses it as a blockage signal. First, the line switching device 1 receives a DC loop from the terminal line 52 as a blockage signal, which is normally received by the DC loop detection circuit 12 (operation procedure 11).
At the same time, it directly connects to the exchange line 53 and transmits a blockage signal (operation step 12). On the other hand, a blockage signal to the direct connection line 51 is detected by the DC loop detection circuit 12 and the signal transmission/reception means 1
4 (operation procedure 12).

FIG. 4 is a flowchart showing an example of the operating procedure when the line switching device 1 connects the direct connection line 51 and the communication terminal device 2 makes a call. First, it is confirmed that the direct connection line 51 is not blocked (operation procedure 21), and the terminal line 5 of the direct connection line 51 is switched by switching the switching circuit 13 of the line switching device.
2 (actuator 111m 22 > 0) Next, when the communication terminal device 2 makes a call and forms a DC loop, the DC loop detection means 16 of the line switching device 1 detects the DC loop from the terminal line. and receives it as a calling signal (operator [23>). According to this operation step 23, the line switching device 1 sends a calling signal formed into a predetermined signal from the signal transmitting/receiving means 14 to the direct connection line 51 (operating step 24). Next, when the connected communication terminal device 2 that has received the calling signal responds, the signal transmitting/receiving means 14 receives a predetermined response signal via the direct connection line 51 (operation procedure 25), and therefore sends the calling signal. is stopped (operation procedure 26), and communication (operation procedure 27) is started.

FIG. 5 is a flowchart showing an example of the operation procedure when the line switching device 1 receives an incoming call from the directly connected line 51.
When a predetermined calling signal is received from 1 (actuator [31) is L, it is confirmed that the communication terminal device is empty (operating procedure 32), the switching circuit 15 is driven, and the direct connection line 51 is connected to the terminal line 52. (Operation step 33) Perform the switching operation. Therefore, the terminal line 42 is connected to the DC loop detection means 16 and the calling signal sending means 17 via the switching circuit 13. The reception of the calling signal from the direct connection line 51 drives the calling signal sending means 17 to send out a calling signal to the communication terminal device 2 to the terminal line 52 (operation procedure 34).Next, the communication terminal device 2 that has received the calling signal [DC loop detection means]
-6 is recognized by detecting a DC loop via the terminal line 52 (operation procedure 35). Therefore, the line switching device stops the calling signal sending means 17 from sending out the calling signal, and
The signal transmitting/receiving means 14 transmits the response signal of the direct connection line 51 (operation procedure 36). The signal transmitting/receiving means 14 detects that the line switching device 1 on the calling side has received the response signal and has stopped the calling signal ( When operation step 37) is performed, transmission of the response signal is stopped (operation step 38), and communication becomes possible. When the communication terminal device 2 is used or blocked in operator j[32, the line switching device 1 sends a blocking signal (operation step 39) according to operation steps 11 and 12 in FIG.
Continuing to step 38, the direct connection line 51 is placed in a blocked state.

Next, the signal transmitting/receiving means 14 of FIG. 2 will be explained with reference to FIG.

FIG. 6 is a functional block diagram showing an example of a signal transmitting/receiving means. The signal transmitting/receiving means connects a signal selection transmitting circuit 151 and a received signal identifying circuit 152 to a direct connection line 51, and these transmitting circuit 151 and identifying circuit 152 are connected to the control means 1.
Connect with 81. The signal selection transmission circuit 151 uses the frequency F1
・Generation circuit 15'3, 154, 1 that generates F2 and F3
55, and in response to a calling command from the control means 181, the output of the frequency F1 generation time l\8153 is transmitted as a calling signal to the direct connection circuit 1151, and similarly, the frequency F2 is transmitted as a response signal to the response command, and the output of the frequency F2 is transmitted as a response signal to the blocking command. Frequency F3 is transmitted to each direct connection line 51 as a blockage signal. The received signal identification circuit 152 identifies the signal transmitted through the direct connection line 51 as a received signal, and notifies the control means 181 of reception of each of the frequencies F1, F2, and F3. Therefore, the control means 1
81 processes reception of frequency F1 from the direct connection line 51 as reception of a calling signal, processes reception of frequency F2 in a calling command as reception of a response signal, and always processes reception of frequency F3 as reception of a blocking signal. do.

In FIG. 6, since the transmitting circuit 151 and the identifying circuit 152 are directly connected to the direct connection line 51, the reception of frequencies Fl and F2 does not directly correspond to the calling signal and response signal. In this case, frequencies and signals can be made to correspond.

〔Effect of the invention〕

As explained above, the present invention is configured such that the line switching device sends and receives signals to the directly connected line, and also detects a DC loop and sends a paging signal to the terminal line. This has the effect of allowing connection to terminal lines under the same conditions as switched lines.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the connections of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIGS. 3 to 5 are flowcharts showing an example of the main operating procedures of the present invention. FIG. 6 is a functional block diagram showing an example of partial details of FIG. 2. 1... Line switching device, 2... Communication terminal device, 3... Exchange, 13... Switching circuit, 14... Signal transmission/reception Means, 15...
・Transformer, 16...DC loop detection means, 1
7... Calling signal sending means, 51... First
2 M T; 3 times Figure 4 Figure 5 M

Claims (2)

[Claims] (1) Line switching that accommodates and connects a terminal line connecting to a communication terminal device on one side and a plurality of various lines connecting to another communication terminal device on the other side, and switches and connects the terminal line to one of the various lines. A line switching device characterized in that the device is provided with a direct connection line that directly connects the line switching device as various lines, and has a signal transmitting/receiving means that is connected to the direct connection line and sends and receives signals using a predetermined signal format. (2) The signal transmitting/receiving means includes a generation circuit that generates a frequency assigned to a signal, and an identification circuit that identifies the frequency received from a direct connection line. line switching device.