JP2605274B2 - Telephone exchange - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone exchange having a function of transmitting a bell signal to an extension telephone, such as a key telephone connected to a plurality of extension telephones and a private automatic exchange.

2. Description of the Related Art The conventional bell signal transmission or ringing system determines which extension should be ringed after detecting an incoming call, and according to a ringing time slot pattern fixedly determined in advance to the extension to be ringed. I was ringing. More specifically, a plurality of extensions are divided into a plurality of blocks each having, for example, three extensions, and a time slot pattern having three ringing time slots (time slots a, b, and c) each having a time difference is set. The ringing time slot is fixedly associated with each extension in the block, such as a time slot a for the first extension, a time slot b for the second extension, and a time slot c for the third extension. . Then, only the extension whose ringing is actually specified in the block is connected to the AC bell signal source in the ringing time slot unique to the extension. For example, even if ringing is designated to one of three extensions in a block, or if ringing is designated to all three extensions, ringing is performed in a time slot unique to each extension.

However, in the above-described conventional method, a ringing time slot is fixedly given to each extension in a block in advance, and the same time slot pattern is used over all of a plurality of blocks. There is a very high probability that extensions to be ringed are concentrated on a specific time slot and a large load is imposed on the power supply at that time, and the power supply capacity must be set to a relatively large value. Was.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a telephone exchange that can reduce the probability that the load on the power supply becomes maximum during ringing.

Means for Solving the Problems The present invention solves the above-mentioned conventional problems. Each time the necessity of ringing arises, the extensions to be ringed are simultaneously picked up, and time is given to each of the picked-up extensions. Time slot signal generating means having different positions on the time axis of the slots are taken out and assigned one by one, and an AC bell signal is transmitted in accordance with the assigned time slot signal.

Operation With the above configuration, each time the need for ringing arises, the time slot signal generating means is set as much as possible within the ringing extension group (the same group in a so-called group call) consisting only of extensions to be simultaneously ringed. Since the time slots are allocated so as not to overlap, the possibility that ringing is performed simultaneously in the same time slot in a plurality of extensions is minimized.

Embodiment Hereinafter, a key telephone that can be connected to a plurality of extension telephones will be described as an embodiment of the telephone exchange according to the present invention. FIG. 1 is a block diagram of the key telephone, FIG.
FIG. 3 is a flowchart showing a main part of a process in the control unit. FIG. 4 shows a pattern of a ringing time slot stored in the memory.

In FIG. 1, reference numerals 101 to 108 are housed extension telephones. 119 is a bell signal source for generating an AC bell signal of about 20 Hz. 110 is the extension interface
A loop current is supplied to the extension telephones 101 to 108 to supply power. Also, the extension interface unit 110 is provided with a relay for ringing to each extension according to a command of the control unit for each extension, and each relay intermittently connects the bell signal source 119 and the extension. Performs ringing to the extension. Reference numeral 111 denotes a central office terminal connected to a line from an external telephone communication network (hereinafter, referred to as an outside line). Reference numeral 112 denotes an office line interface unit for matching with an outside line, and has a function of notifying the control unit of an incoming call from the outside line. Reference numeral 113 denotes a communication path switch unit, which connects each extension and connects an extension with an external line according to a command from the control unit. A control unit 114 controls the call path switch unit 113 and detects an incoming call in the office line via the office line interface unit 112, controls the extension interface unit 110, and controls ringing of the extension. A memory 115 stores a ringing phase pattern. More specifically, as shown in FIG.
(Read only memory). At the time of ringing control, the control unit 114 reads out and refers to this.

Next, a control procedure of the control unit 114 and an actual operation example will be described.

FIG. 2 shows a process of allocating a time slot when there is an incoming call from the outside. That is, when an incoming call is received from an external line, it is necessary to transmit an AC bell signal for ringing to other extensions except for an extension to which the terminal is not connected and an extension that is already in a call. When an incoming call is received from an outside line, first, an extension to which an AC bell signal is to be actually transmitted and a time slot to which the bell signal source is connected are specified.

In FIG. 2, a step 201 is for determining whether or not it is necessary to perform ringing on an extension. Step 202 is for confirming whether any time slot has already been designated and ringing has been performed. Step 203 is a step of updating the time slot number by adding 1 to the time slot number storage table storing the specified time slot number. 204 is a step of storing the data of the time slot number storage table in a dedicated table of the designated extension. Step 205 is for confirming that the processing for all extensions has been completed. If it is determined that ringing needs to be performed on the extension designated in step 201, the process proceeds to a setting routine including steps 202, 203, and 204. On the other hand, if there is no need to perform ringing on the extension designated at step 201, the above setting routine is skipped. In step 205, when it is confirmed that the processing has not been completed up to the last extension, the next extension is designated, and it is determined whether or not it is necessary to perform ringing for the next extension by returning to step 201. Done.

FIG. 4 shows the time position of each time slot and the memory 11.
5 shows an array of data in 5. The data is stored in the memory 115 in a 4-bit digital format, and each digit corresponds to four types of time slots. The data of "1" instructs the transmission of the AC bell signal, and the data of "0" instructs the interruption of the AC bell signal.

The actual ringing operation is performed according to the control procedure shown in FIG. The microcomputer provided in the control unit 114 performs an interrupt process every 250 ms.
It is programmed to execute the timer interrupt processing shown in the figure. In FIG. 3, in step 206, it is determined whether or not the execution of ringing is set in the extension dedicated table. In step 207, the time slot number set in the extension dedicated table is used to determine the correspondence in the memory 115. Extracts one digit of digit data,
A process for storing in the relay control table is performed. In step 208, if the data in the relay control table is 1, the relay is fixed to the ON state, and if the data is 0, the relay is fixed to the OFF state. On the other hand, if it is determined in step 206 that ringing is unnecessary, the relay corresponding to the extension remains OFF. Step 209 is for confirming that the processing for all extensions has been completed. If it is determined in step 209 that the processing has not been completed up to the last extension, the next extension is designated, and the process returns to step 206 to perform the processing for the next extension. On the other hand, if it is confirmed in 209 that the processing has been completed up to the last extension, the interrupt processing ends.

Next, an operation example will be described. However, there is an incoming call on the office line,
On the other hand, it is assumed that extensions 101 to 106 are ringing extensions, that is, the same group extension in the group calling function.

First, when there is an incoming call from the office line 111, the control unit 114 detects this via the office line interface unit 112. When it is detected that there is an incoming call, the four ringing time slots are allocated while checking the extension from which the call signal must be transmitted next. Explaining based on FIG. 2, first, it is checked whether or not the extension 101 has to ring, and if ringing has to be performed,
Moving to the next step 202, a time slot is allocated. It is assumed that time slot 1 is set to extension 101 in step 202, for example. In the same manner, scanning is performed over all extensions, and at that time, all the extensions to be ringed are assigned time slots. Time slot 2 is assigned to extension 102, time slot 3 is assigned to extension 103, time slot 4 is assigned to extension 104, time slot 1 is assigned to extension 105, and time slot 2 is assigned to extension 106. The information is stored in a dedicated table for each extension. You. But extension
In 107, since no ringing is performed, no time slot is assigned, and information indicating that no ringing is performed is stored in the table.

Ringing is performed according to data in a relay control table provided for each relay. The data in the relay control table is updated by the timer interrupt process started every 250 msec as described above. For extensions that do not ring (for example, extension 107), the relay in extension interface 110 remains OFF. On the other hand, ON data is written into the relay control table only for the extension for which ringing is designated, and the data in the relay control table is stored in the time slot pattern stored in the memory 115 (see FIG. 4). According to
Since the relay is turned ON or OFF, the relay also repeats ON and OFF according to the time slot pattern.

Effects of the Invention As described above, according to the present invention, each time the need for ringing arises, extensions to be ringed are simultaneously picked up, and the positions of the time slots on the time axis differ for each of the picked-up extensions. By assigning the time slot signal generating means one by one and transmitting an AC bell signal according to the assigned time slot signal, each time the need for ringing arises,
Since the time slot signal generating means is assigned so that time slots do not overlap as much as possible within a ringing extension group composed of only extensions to be ringed at the same time, ringing is performed simultaneously in a plurality of extensions at the same time slot. The possibility is kept to a minimum and the transmission of the AC bell signal can be minimized to concentrate on a certain time slot. Therefore, the load on the power supply can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a key telephone set according to an embodiment of the present invention, FIGS. 2 and 3 are flowcharts showing a processing procedure of a control unit in the key telephone set, and FIG. FIG. 4 is a timing chart showing an image of time slot data stored in a memory. 101 to 108: extension telephone 119: bell signal source 110: extension interface unit 111: office line terminal 112: office line interface unit 113: communication line switch unit 114: control unit 115: memory is there.

Claims (1)

(57) [Claims] In a telephone exchange provided with a group call function for simultaneously calling a plurality of extensions in response to an incoming call from a certain office line, a bell signal for transmitting a bell signal to each of the extensions is provided. A relay for connecting the bell signal source to each of the extensions; a plurality of time slot signal generating means for transmitting time slot signals having different positions on the time axis from each other; Picking up a plurality of extensions to be ringed corresponding to the station line where the call arrived, and providing one of the plurality of time slot signal generating means to each of the picked up extensions. A control for controlling the relay so as to take out and assign the AC bell signal to the extension in accordance with the assigned time slot signal. A telephone exchange characterized by having a control means.