JPS6310994A - Line exchange - Google Patents

Abstract

PURPOSE:To easily extend equipments by providing the exchange of the same function as an existing exchange and an extended exchange having exchange switches of n<2>/2 at the maximum. CONSTITUTION:A line exchange is constituted of a circuit connected to an external line, a circuit for exchanging the external circuit and an internal circuit, a circuit for transmitting control information between equipments connected to the internal line, a selection means for extending the line and an extended line. The extended exchange means 13 for controlling the extended line and a control information line is provided, the existing exchange devices 11, 12 are effectively used to extend the line. According to such constitution, at the time of extending to the (n) sets of the exchanges, the shoulder lines of stored lines (xn) of one exchange can be virtually made access at the time of viewing from the equipment connected to the extension of one exchange with a simple constitution of (n) pairs of the extended lines, the n<2>/2 change over switches and a CPU controlling them.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small-scale line switching device for exchanging public telephone lines and extension lines of several circuits to more than 10 central offices.

2. Description of the Related Art Conventionally, means for exchanging public telephone lines, etc. with extension lines within premises or in a home have ranged from large-scale telephones that can handle several hundred lines to main telephones and child telephones that are commonly used in homes. A variety of small-scale devices such as parent-child telephones have been announced.

In addition, the method of line switching equipment, which has a maximum of two external lines and a maximum of three internal lines, and a control information transmission line for mutually transmitting between devices connected to the internal lines, is becoming standardized, and various It has been announced.

FIG. 2 shows a conventional example of a switching device having a maximum of two external lines and a maximum of three internal lines. In the figure, 21 is a switching device, 22.28 is a switching circuit, 23.29 is a switching switch constituting 22.28, 24.210 is a microprocessor (CPU), 25.27 is a control information line interface circuit, and 26. is a telephone device, 211 is a device with a telephone function, 212 to 214 are extensions, and 215 is! ! i'l is the elevation information line.

The operation will be explained based on FIG. First, when the device 211 having the telephone function is not in an off-hook state and the CPU 210 detects this state, the CPU 210 sends the information to the switching device 21 via the interface circuit 26 to the control information line 215 according to a predetermined packet format. C.P.
A call request is made to U24. The switching device 26 notifies the telephone device 211 of the callable and usable extension number.

For example, if the extension 212 is available, the number is notified and each device turns on its own exchange switch. In this state, the dial tone transmitted from the switching device (not shown) of the central office reaches the telephone device side, and the telephone device 26 transmits the dial tone to the switching device 21 via the control information line 216.
to transmit your phone number. The exchange device 21 dials the received number to the central office exchange, and after receiving the ring pack tone from the central office exchange, the call becomes possible.
As shown in the figure.

Problems to be Solved by the Invention In the case of the switching equipment shown in the conventional example, when attempting to add external lines, it is necessary to install multiple switching equipment with the same function and use each one independently, or to install a switching equipment with a higher capacity. In the former case, existing switching equipment can be utilized, but on the other hand, it is necessary to use external switching equipment when making extension calls between telephone equipment connected to each extension. or even if the external line of the first exchange is busy and the external line of the second exchange is free, the telephone equipment connected to the first In the latter case, the existing switching equipment cannot be used effectively. The present invention has been made in view of these points. This allows external lines to be added while maintaining compatibility with the functions of the existing switching equipment.Furthermore, even if multiple switching equipment with the same functions are installed, the equipment connected to one extension line will be connected to the other. An object of the present invention is to provide a line switching device that allows free access to equipment connected to the extension lines of the switching device. A circuit to connect and a circuit to exchange an external line and an internal line,
In addition to the circuit that transmits control information between devices connected to the internal line, there is also a selection means for line expansion and an expansion line.
The line switching device is configured with an expansion switching means for controlling the expansion line and the control information line, so that the line can be expanded while effectively utilizing the existing switching device.

Effects of the Invention With the above configuration, even when expanding to n units of switching equipment, the present invention has a simple configuration of n pairs of extension lines, n/2 changeover switches, and a CPU that controls them, and the extension lines of one switching equipment can be expanded to n units. FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 1 is a block diagram showing an embodiment of the present invention. .

In the figure, 11.12 is a switching device, 13 is an expansion switching device, and 14
．． 15 is a device having a telephone function that is connected to the extensions of the switching devices 11 and 12, respectively; 16 to 18; 20 to 22 are the extensions of the switching devices 11 and 12, respectively; 19 and 23 are respective control information lines; .25 are the respective extension lines as well. fJ et al., Kaya Imoko Sou 1 + Sequence 1
When the telephone 14 connects to an external line, and the external line 11.1 of its own switching device 11
The case where 2 is in use will be explained. First, the telephone 14 detects off-hook and issues a call request via the control information line 19. This call is transmitted to switching equipment 11 and expansion switching equipment 13. Expansion switching equipment does not respond unless the external line of another switching equipment is free◇
At this time, the outgoing call notification issued by the switching device 11 is
It is transmitted to telephone 14. If the external line of another switching device is vacant, the expansion switching device B transmits to the control information line 19 an extended call permission which has a higher priority than the call prohibition of the switching device 11. This notification is sent to the telephone 14 as well as to the switching device 11.
The exchange device 11 selects and turns on the exchange switch for expansion exchange, and at the same time sends a call to the telephone 14 to notify the available extension number. When the telephone 14 receives this, it turns on the exchange switch corresponding to the designated extension.

After the extended switching device 13 issues an extended call request, it turns on its own exchange switch and issues an extended call request to the switching device 12. When the exchange device 12 receives this, it turns on the exchange switch for expansion exchange.

A call is made to the expansion switching device 13 indicating that the call is allowed. at this point
The loop is closed to the central office exchange (not shown), and the dial tone reaches the telephone 14 via the exchange 12, the extended exchange 13, and the exchange 11.

When the dial tone arrives, the telephone number is transmitted from the telephone set 14 to the expansion switching device 13, and from the expansion switching device 13 to the switching device 12 through the control information line 23, and the switching device 12 sends a dial to the office. The call is established after a ringback tone is sent from the station.

At the end of the call, the telephone 14 detects on-hook and transmits an end notification to the switching device 11 and the expansion switching device 13.

The exchange device 11 that received the message turns off its own expansion exchange switch and opens the loop. The expansion exchange device 13 issues an expansion end notification to the exchange device 12, and the exchange device 1 that received the notification
Step 2 turns off the exchange switch and ends the process.

Effects of the Invention As described above, according to the present invention, even when expanding the line capacity, while utilizing the existing switching equipment, the maximum number of switching equipment with the same function as the existing switching equipment and the total number of switching equipment n n
It can be easily expanded by simply providing an expansion exchange device having two /2 exchange switches, and is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a line control device according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional line control device having two external lines, three internal lines, and a control information line, and FIG. FIG. 4 is a diagram showing a calling sequence in a conventional example, and FIG. 4 is a diagram showing a calling sequence in an embodiment of the present invention. 11.12...Switching device, 13...Expansion switching device, 14.15...Telephone, 16-1
8...Extension of exchange device 11, 19...
Control information line of switching device 11, 20-22...extension line of switching device 12, 23...control information line of switching device 12. Name of agent: Patent attorney Toshio Nakao and one other person
&Application 3rd figure

Claims (1)

[Claims] means for connecting to an external line, means for exchanging the external line and internal line, means for transmitting and receiving control information via a control information transmission line that transmits control information between devices connected to the internal line, and other means for exchanging control information between devices connected to the internal line. an extended line selection means for exchanging an external line and an internal line or an external line and another internal line; a line switching means having an extended line; It has an expansion exchange means consisting of a maximum of n^2/2 switching devices for exchanging n pairs of expansion lines of the means, and is characterized by maintaining functional compatibility and easily expanding the line. circuit switching equipment.