JPH03243028A - Method and device for setting up radio channel to cordless terminal - Google Patents

Abstract

PURPOSE:To prevent respective terminals from using the same channel to prevent the collision of communication by specifying respectively different radio channels to respective cordless terminals, and allowing each terminal to use its specified radio channel. CONSTITUTION:A calling signal received by a connection device 200 is sent from a transmitting circuit 32 to a radio data interface circuit 36d, the identification(ID) number of a slave machine 300 included in the calling signal is compared with an ID number read out from an EEPROM 43, and when both the numbers coincide with each other, the calling signal is sent to a CPU 36a. The CPU 36a transmits a calling channel specification request to a master device 100 through a control signal line 19 in response to the calling signal. At the time of receiving a channel specification request, the master device 100 selects one of idle communication channels from local idle calling channel data recorded in a RAM 16 and returns its numbered data to the device 200 as a calling channel specification. When the device 200 receives the calling channel specification, a control part 36 transmits a calling response signal to the slave machine 300, which switches the current channel to the specified calling channel.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a telephone system, such as a key telephone system or a home telephone system, which connects a center and a plurality of terminals, and which includes a cordless terminal. The present invention relates to a method and apparatus for setting up a wireless channel between each cordless terminal and a center in a system including the above.

(Prior Art) A general system configuration of a key telephone system including a cordless terminal will be explained with reference to FIG.

This system includes a main device 3 having a control function connected to an outside line 1.2, and a plurality of extension terminals connected to the main device 3. The extension terminals include a wired button telephone terminal 8.9 as well as a cordless terminal 4.5.6.7.

The cordless terminal is a mobile cordless handset5.
7, and a connecting device 4.6 for relaying communication between each child device 5.7 and the main device 3.

Here, the connection device 4 forms a pair with the slave device 5, and the connection device 6
forms a pair with the handset 7, and each pair constitutes one cordless terminal. Each cordless terminal, like other wired button telephone terminals, is capable of making/receiving calls and talking to outside lines through the main device 3, and making/receiving calls and making calls to other terminals via extension lines.

Channels that can be used for wireless communication in each cordless terminal are defined, for example, as shown in Table 1.

Table 1 In Table 1, channel C-C11 is called a control channel, and conventionally, this control channel is always used to start communication when a call is made or when a call is received. On the other hand, channel 5-CH
I to S-CH2O are called communication channels, and after communication starts, the channel used is switched from the control channel to one designated communication channel. A multi-channel method is adopted for communication channels, and interference with other cordless terminals is avoided by specifying one of the available communication channels as the channel to be used in the sequence using the control channel at the start of communication. ing.

A full-duplex system is used for wireless communication at each cordless terminal, and different frequencies are assigned to the upstream channel for transmission from the handset to the connected device and the downstream channel in the opposite direction. As shown in Table 1, once the number of the communication channel to be used is determined, the frequencies of the upstream channel and the downstream channel are uniquely determined. In addition,
FM or PM is used as the modulation method.

FIG. 10 shows a connection operation sequence when a call is made from a cordless terminal to an outside line in this type of conventional system. In the communication between the cordless handset and the connected device in the diagram,
Control channels are indicated by dashed arrows, and communication channels are indicated by solid arrows.

Before making a call, the cordless terminal is in a standby state and the channel in use is set to the control channel.

When the cordless handset goes off-hook in this standby state, the handset transmits a calling signal to the connecting device through the control channel, as shown in FIG.

This calling signal includes the identification code of the handset. If the connecting device's identification code matches its own identification code, it responds to the calling signal, designates - of the previously recognized empty communication channels as the channel to be used, and sends a call response signal to the handset. Send it back. This call response signal includes information indicating the designated communication channel.

Thereafter, both the connecting device and the handset switch the channel in use from the control channel to the specified communication channel.

After confirming the availability of this communication channel again, the handset transmits a channel switching completion signal through this communication channel. From then on, this call channel is used until the end of the call.

FIG. 11 shows a connection operation sequence when a cordless terminal receives an incoming call from an outside line in a conventional system. FIG. 12 is a time chart showing the operations of the handset and the connecting device in this case.

Before receiving a call, the cordless terminal is in a standby state. In this standby state, the handset uses the transmitter circuit (
TX) is turned off, and the receiving circuit (RX) is turned on intermittently.
It is repeatedly turned off (for example, off for 2 seconds and on for 60 milliseconds).

On the other hand, the transmitting circuit of the connecting device is turned off and the receiving circuit is turned on.

In this state, when a call arrives at the main device from an outside line, the first
1. As shown in Figure 12, an incoming call command is sent from the main device to the connected device. Then, the connecting device designates one of the idle communication channels recognized in advance as the channel to be used, turns on the transmitting circuit, and sends an incoming signal to the handset through the control channel. This incoming signal includes information indicating the designated communication channel. This transmission of the incoming call signal is repeated until the incoming call response signal is received from the handset or a predetermined time limit (for example, 3.7 seconds) has elapsed.

If an electric field is detected when the receiving circuit is turned on, the handset maintains the on state. When the above-mentioned incoming call signal is received, the transmitting circuit is turned on and an incoming call response signal is sent to the connecting device through the control channel.

Thereafter, the handset temporarily turns off its transmitting circuit, switches the channel in use to the designated communication channel, and then turns on its transmitting circuit again to transmit a channel switching completion signal.

When the connecting device receives the incoming call response signal, it stops sending out the incoming call signal, temporarily turns off the transmitting circuit, and switches the channel in use to the specified communication channel. After that, when the above channel switching completion signal is received from the handset,
The transmitting circuit is turned on again, and an incoming ringing signal is repeatedly sent to the slave device each time a ringing tone command is received from the main device. The handset sounds a ring tone every time it receives an incoming ringing signal.

(Problems to be Solved by the Invention) As described above, in the conventional system, a cordless terminal always uses a control channel when starting communication. In particular, in the case of an incoming call, - cordless terminals may occupy the control channel for several seconds.

There is one control channel, and while this is occupied by - terminals, other terminals cannot use the control channel.

As a result, problems such as those illustrated below occur.

(1) When a call is received at a certain cordless terminal, other cordless terminals do not make or receive calls for a while immediately thereafter.

(2) As shown in FIG. 13, the handset 5 of the first cordless terminal is placed near the connection device 6 of the second terminal,
If the handset 7 of the second terminal is placed near the connection device 40 of the first terminal, if a call arrives to these two terminals at the same time, each handset receives a strong signal from the connection device located nearby. Only radio waves will be received, and due to a mismatch in the identification numbers, there will be no ringing.

Therefore, an object of the present invention is to enable two or more cordless terminals to simultaneously make and receive calls in the above system.

[Structure of the invention]

(Means for Solving the Problems) A first aspect of the present invention provides wireless channels to be used by each cordless terminal in a telephone system having a center and a plurality of cordless terminals communicably connected to the center. In the setting method, the center selects the wireless channels to be used by each cordless terminal from a predetermined group of wireless channels so as not to overlap each other, and the center selects each selected wireless channel for each cordless terminal from a predetermined group of wireless channels. A wireless channel setting method is provided, which includes a step of notifying a wireless channel, and a step of storing the wireless channel notified at each cordless terminal and using the stored wireless channel.

Further, a second invention provides a device for setting a wireless channel to be used by each cordless terminal in a telephone system having a center and a plurality of cordless terminals communicably connected to the center. channel selection means for selecting a wireless channel to be used by each cordless terminal from a group of wireless channels so as not to overlap with each other; and channel specifying means for notifying each cordless terminal from the center of each selected wireless channel. and channel storage means for storing the notified radio channel in each cordless terminal, and channel control means for making the radio channel to be used in each cordless terminal coincide with each of the stored radio channels. A wireless channel setting device is provided.

Furthermore, in addition to the above configuration, the device according to the third invention investigates the availability/usage status of each channel of the predetermined wireless channel group in each cordless terminal to obtain local availability channel information, and transmits this information to the center. The channel selection means further comprises a local air channel information investigation means for notifying the
The present invention is characterized in that a wireless channel to be used by each terminal is selected from among the wireless channels indicated as empty by local empty channel information from each terminal in the predetermined group of wireless channels.

Further, in the device according to a fourth aspect of the present invention, the channel selection means preferentially selects radio channels whose frequencies are not adjacent to each other from among the predetermined radio channel group as radio channels to be used by each cordless terminal. It is characterized by

Furthermore, a fifth invention provides a channel clearing means for erasing the wireless channel stored in the selected cordless terminal, and responding to the operation of the channel clearing means, in order to change the wireless channel used by the selected cordless terminal. change channel selection means for selecting a new wireless channel from the predetermined group of wireless channels that is different from either the erased wireless channel or the wireless channels stored in other cordless terminals; The cordless terminal further includes change channel specifying means for notifying the cordless terminal of the selected new wireless channel, and the channel storage means stores the notified new wireless channel, so that the cordless terminal can thereafter change the new wireless channel. To provide a wireless channel setting device that uses a wireless channel.

(Function) In the device according to the present invention, the wireless channels to be used from the center are specified for each cordless terminal so as not to overlap with each other. Each cordless terminal uses its designated wireless channel from beginning to end when performing wireless communication. Therefore, once the channel designation is completed, there will be no collision of communications between multiple cordless terminals on the same channel.

(Embodiment) Hereinafter, an embodiment of the wireless channel setting device according to the present invention will be described with reference to the drawings.

FIGS. 1, 2, and 3 show the configurations of a main device, a connecting device, and a slave unit when the present invention is applied to a button telephone system having the system configuration as shown in FIG. 9 already described. .

As shown in FIG. 1, the main device 100 includes an outside line interface circuit 10.11, a key telephone (EKT) interface circuit 13.14, a call exchange circuit 12, and a control section 15.
, a power supply circuit 24, and other circuits.

Each outside line interface circuit 10.11 is connected to the central office line 1.2, respectively.
The control unit 15 detects the calling signal from each station line.
a function to capture each office line according to control data from the control unit 15, a function to send a selection signal to the captured office line according to control data from the control unit 15, a function to communicate between the captured office line and the call switching circuit 12. It has functions such as transmitting audio signals between the two.

Each EKT interface circuit 13.14 is connected to an extension terminal, such as a wired key telephone (EKT) or cordless terminal, via an audio signal line 18.20 and a control signal line 19.21. Each EKT interface circuit has a function of supplying power to each extension terminal, a function of transmitting voice signals between each extension terminal and the call switching circuit 12, a function of transmitting control data between each extension terminal and the control unit 15, etc. The data interface circuit 17 includes a necessary buffer memory, parallel/serial conversion circuit, etc., for transmitting control data.

The telephone exchange circuit 12 is an external line interface circuit 10.11.
and EKT interface circuit 13.14,
In accordance with control data from the control unit 15, exchange is performed between the central office line and the extension terminal. This switching circuit 12 is further connected to an oscillator 22 that generates an extension dial tone (400H2), and when a call is received from an extension terminal, the calling side's E
This oscillator 22 is connected to the KT interface circuit and sends an extension dial tone to the calling terminal. Note that any exchange method may be used.

The control unit 15 is a unit that controls various operations of this system such as calling, receiving, connecting, talking, and ending calls.
5a, ROM 15b in which control programs are stored, RA
It is equipped with a microcomputer including an M15c, etc., and is controlled by a stored program method. In this control, necessary control data is transmitted between the control unit 15, the external line interface circuits 10 and 11, and the EKT interface circuit 13.
．． 14 and the telephone exchange circuit 12.

The control program includes a program for specifying a communication channel to be used according to the present invention for each cordless terminal connected to the main device. This program is executed as part of the initial routine when the power is turned on, for example. This control section 15 further includes R
AM16 is connected. This RAM 16 contains preset possible functions of each extension terminal, communication channels to be used by each cordless terminal designated according to the present invention,
A table is created that records the information. The RAM 16 is backed up by a lithium battery 25 so that the records in this table are retained even in the event of a power outage.

The power supply circuit 24 is a circuit that converts a commercial 100V AC power source into a stabilized DC power source at a predetermined voltage level, and supplies the converted DC power source to the main device 100. A portion of the supplied power is supplied from each EKT interface circuit 13, 14 to each extension terminal, as already mentioned.

Next, referring to Figure 2, the cordless terminal connection device (CE
) is explained below.

This connecting device 200 is connected to the EKT interface circuit (eg 13) shown in FIG. 1 via an audio signal line 18 and a control signal line 19. This connection device 200 includes a hybrid circuit 30, a receiving circuit 31, a transmitting circuit 32, a transmitting circuit (TX) 34, a receiving circuit (RX) 38, and a control unit 3.
6, a power supply circuit 41, etc. are included.

The hybrid circuit 30 performs 2-wire/4-wire conversion between the audio signal line 18 from the main device 100 and each audio signal line from the receiving circuit 31 and the transmitting circuit 32. This circuit 3
0 has a balancing network 33, which simulates the impedance of the line and suppresses side noise to an appropriate amount.

The receiving circuit 31 sends the audio signal (receiving signal) output from the hybrid circuit 3o to the transmitting circuit 34. The transmitting circuit 34 is given a local oscillation signal for transmission by the PLL circuit 35, and the control unit 3 sets the frequency to match the downlink channel frequency (see Table 1) of the radio channel to be used.
6. The output signal of the transmitting circuit 34 is sent to the antenna 45 through the antenna duplexer 37, and wirelessly transmitted to the slave device.

The signal transmitted from the handset is received by the antenna 45 and input to the receiving circuit 38 through the antenna duplexer 37.

A receiving local oscillation signal is supplied to this receiving circuit 38 from a PLL circuit 39, and its frequency is controlled by the control unit 36 so as to match the upstream channel frequency (see Table 1) of the radio channel to be used. The transmitting circuit 32 sends the audio signal (transmitting signal) output from the receiving circuit 38 to the receiving hybrid circuit 30 .

A power supply circuit 41 and a data interface circuit 42 are connected to the data line 19 from the main device 100 via a transformer 40 . The power supply circuit 41 receives power supplied from the main device 100, converts it into stable DC power at a predetermined voltage level, and supplies the DC power to the connection device 200. Data interface circuit 4
Reference numeral 2 is for transmitting control data between one data line and the control unit 36, and includes a serial/parallel conversion circuit, a buffer memory, etc. necessary for this purpose.

The control unit 36 includes a receiving circuit 31, a transmitting circuit 32, and a transmitting circuit 3.
4. It is for controlling the status of the PLL circuit 35, 39, etc., and the CPU 36a and the RO where control programs are stored.
It has a microcomputer consisting of M36b SRAM36c and performs control using a stored program method. The control unit 36 also includes a wireless data interface circuit 36d that includes a modem. This interface circuit 36d transmits the audio frequency signal from the handset to the transmitting circuit 32.
, demodulates the control data and provides it to the CPU 36a,
Further, control data to be transmitted from the CPO 36a to the handset is modulated into an audio frequency signal and sent to the receiving circuit 31. Furthermore, this control section 36 also exchanges control data with the main device ]00 via the data interface circuit 42.

An EEPROM 43 and an audio channel clear switch 44 are connected to the control unit 36 . The EEPROM 43 records the identification number of this cordless terminal and the communication channel designated by the main device 100 to be used by this terminal. Accordingly, the control section 36 controls the frequency of the PLL circuits 35 and 39. The call channel clear switch 44 is
When this is turned on, the control unit 36 erases the record of the communication channel to be used in the EEPROM 43, and returns the state of the connection device 200 to the state before the channel to be used was specified. This switch 44 is used, for example, when re-designating the channel to be used when the radio wave condition of the designated communication channel is poor. A similar clear switch is also provided on the handset, and in the above case, it is also necessary to press the clear switch on this handset.

Next, the configuration of the cordless handset will be explained with reference to FIG.

Child $1300 includes antenna 73, receiving circuit 51, receiving circuit (RX) 53, receiver 54, transmitter 55, transmitting circuit 5
6. Transmission circuit (TX) 57, control unit 59, sounder 63
, a power supply circuit 66, a dial, a function button 68, and the like.

Radio waves transmitted from the connection device 200 are received by the antenna, passed through the duplexer (DUP) 50, and then sent to the reception circuit 51.
is input. The receiving circuit 51 receives a receiving local oscillation signal from the PLL circuit 52.

The frequency of this PLL circuit 52 is controlled by a control unit 59 to match the downlink channel frequency of the radio channel to be used. The output signal of the receiving circuit 51 enters the receiver circuit 53 and is output to the receiver 54.

The audio signal from the transmitter 55 enters the transmitting circuit 56 and is sent to the transmitting circuit 57. The transmitting circuit 57 receives a transmitting local oscillation signal from the PLL circuit 58.

The frequency is controlled by the control unit 59 to match the uplink channel frequency of the radio channel to be used. The output signal of the transmitting circuit 57 is sent to the antenna 73 through the antenna duplexer 50 and transmitted to the connected device.

The control unit 59 includes a receiving circuit 51, a receiving circuit 53, and a transmitting circuit 5.
6. It is for controlling the states of the transmitting circuit 57, PLL circuits 52, 58, etc., and has a microcomputer consisting of a ROM 59b and a RAM 59C that store a CPU 59a1 control program, and performs control using a stored program system. This control unit 59 also has a wireless data interface circuit 59d that includes a built-in modem, and this interface circuit 59d receives control data converted into an audio frequency signal received from the connection device 200 from the receiver circuit 53, demodulates it, and demodulates it. Send to CPU59a, and also send to CPU59
The control data to be transmitted to the connected device outputted from a is modulated into an audio frequency signal and sent to the transmission circuit 56.

An EEPROM 60 and a speech channel clear switch 61 are connected to the control section 59 . As in the case of the connection device 200, the identification number of this terminal and the communication channel to be used designated by the main device 100 are recorded in the EEPROM 60, and the communication channel clear switch 61, when turned on, clears the communication channel of this terminal. The state is returned to the state before the channel to be used was specified.

This control unit 59 also includes a sounder 63, a dial and function button 68, a hook button 69, a call lamp 70,
An out-of-service lamp 70 and the like are connected. The sounder 63 outputs a ringing tone signal when a call arrives, and a confirmation tone signal when the dial and function button 68 is pressed.
from the amplifier 62. The dial and function button 68 is pressed when performing dialing, function selection, and the like. The six hook buttons are switches that are turned on when pressed once and turned off when pressed again, and the control unit 59 recognizes that when the button is on, the slave unit is off-hook, and when it is off, it is on-hook. The call lamp 70 is turned on by the control unit 59 during a call. The out-of-range lamp 71 is turned on by the control unit 59 when the handset goes out of the range of radio waves from the connected device.

The power supply circuit 66 regulates the output voltage of the nickel cadmium battery 65 to a predetermined level and supplies it to the slave unit 300. This power supply circuit 66 has a charging terminal 67, and by connecting an external charger (not shown) to this, the battery 6
5 can be charged. The power switch 64 switches the power supply circuit 66 to prevent battery consumption when the handset 300 is not used at all.
This is a switch to turn off the

Next, the operation of this button telephone system will be explained.

For example, once the installation and wiring work of this system is completed,
The construction worker turns on the power to the main device 100.

First, an initial routine is executed to initialize data necessary for the operation of this system (for example, the extension number of each terminal and possible functions). This initial routine also includes a procedure for specifying the call channel to be used by each cordless terminal according to the present invention. FIG. 4 shows the operation sequence for specifying this channel.

When the main device 100 is powered on, power supply to the connection device 200 is started. In the connection device 200, first, the control unit 3
6 turns on the receiving circuit 38 and the transmitting circuit 32, scans the local oscillation frequency of the PLL circuit 39 over the entire range, and based on the noise detection signal (ND) from the transmitting circuit 32 at each frequency at that time. Then, the availability/usage status of all communication channels locally at the installation location of this connection device 200 is investigated. The resulting number data of empty or used communication channels (see Table 1 for channel numbers) is sent to the main device 100 through the control signal line 19. Hereinafter, this data will be referred to as local idle channel data. In the main device 100, the control unit 15 receives and totals the local free call channel data from all connected devices, and records the data in a table in the RAM 16.

After this, the construction worker presses six hook buttons on a certain cordless handset 300 to turn it on. Then, this slave unit 3
The control unit 5 of 00 recognizes off-hook and transmits the transmitting circuit 5.
6 and the transmitting circuit 57 are turned on, and a calling signal is sent to the transmitting circuit 56 through the wireless data interface circuit 59d.

In this initial state, the channel used by handset 300 is set to the control channel. The channel used by the connection device 200 is also set to the control channel after the above scanning is completed. Therefore, the calling signal is transmitted from handset 300 to connecting device 200 through this control channel.

The calling signal received by the connecting device 200 is sent from the transmitter circuit 32 to the wireless data interface circuit 36d, where the identification number of the handset 300 included in the calling signal and the age-specific number read from the EEPROM 43 are sent to the wireless data interface circuit 36d. are compared,
If they match, this calling signal is sent to the CPU 36a. C
In response, the PU 36a sends a communication channel designation request to the main device 100 via the control signal line 19.

When the main device 100 receives the channel specification request,
The control unit 15 selects one free call channel from among the local free call channel data recorded in the RAM 16, and sends the number data back to the connection device 200 as a call channel designation.

In the connection device 200, upon receiving this call channel designation, the control unit 36 transmits a call response signal to the handset 300. This call response signal includes the number data of the designated communication channel. Transmission of this call response signal is performed using a control channel.

Thereafter, in the connection device 200, the channel to be used is switched from the control channel to the specified communication channel.

When the handset 300 receives the call response signal, the controller 59 controls the PLL circuit 35.39 to switch the channel in use from the control channel to the designated call channel, and then checks whether the call channel is free or not. Receiving circuit 53
Confirmation is based on the carrier detection signal (CD) from. When it is confirmed that the channel is empty, the control unit 5 transmits a channel switching completion signal to the connection device 200. This transmission is performed using the specified communication channel. After this, the control section 59
EEPR the number data of the call channel specified above.
Register on OM60.

In the connection device 300 , upon receiving the channel switching completion signal from the handset 300 , the control unit 36 transmits an off-hook signal to the main device 100 and transmits an audio circuit on signal to the handset 300 . Further, the control unit 36 registers the number data of the specified communication channel in the EEFROM 43.

In the main device 100, upon receiving the off-hook signal, the control section 15 transmits the number data of the specified communication channel to the R.
Register in the table in AM16. In addition, the control unit 15
controls the telephone exchange circuit 12 to connect the oscillator 22 and the EKT interface circuit 13, and transmits the extension dial tone from the oscillator 22 to the connecting device 2 through the voice signal line 18.
00. The connecting device 200 transmits the extension dial tone received from the audio signal line 18 to the handset 300.

In the handset 300, the control section 59 receives the audio circuit ON signal and switches the audio circuits (in the receiving circuit 53 and the transmitting circuit 56) to connect the receiver 54 and the transmitter 55 to the receiving circuit 51 and the transmitting circuit 57, respectively. (the circuit to be connected) is turned on. Therefore,
The received extension dial tone is sent to the handset 54. Upon hearing this, the construction worker knows that the registration of the call channel to be used for this terminal has been completed.

After this, the construction worker presses the hook button 69 of this slave unit 300 again to turn it off. As a result, the handset 300
The control unit 59 recognizes on-hook and sends a call termination signal to the connection device 200. Connecting device 200 receives this on-hook signal and sends it to main device 100. As a result, main device 1
00 recognizes that the channel designation procedure for this cordless terminal has been completed.

When the channel designation for one terminal is completed in this way, the other cordless terminal is then taken off-hook, and the call channel designation is performed for that terminal in the same sequence as above. This is repeated for all cordless terminals.

FIG. 5 shows an example of a table formed in the RAM 16 of the main device 100 after completion of specifying communication channels for all cordless terminals. This table includes a map of designated call channels and a map of local free call channels. In this example, the identification numbers “1” to “4”
There are four terminals, of which terminal type "1" is a cordless terminal and terminal type "0" is a button telephone.

In the designated call channel map, channels marked with "1" are designated call channels.

Also, in the local free call channel map, “O
” or an empty channel.

By the way, when sequentially specifying the communication channels to be used by each cordless terminal, it is necessary to ensure that the specified communication channels do not overlap with each other. Therefore, channel designation by the main device 100 is performed according to the selection order as shown in FIG. 6, for example.

That is, for the first terminal, communication channel number 1 (S-C
Specify call channel number 6 (S-HI) for the next terminal.
CH6), then number 11, and so on, specifying every fifth number. Then, after specifying up to the last number 86, the next 2
Go back to the number and specify every 5th number. At that time, the fifth
Channels in use marked with "1'" in the local idle call channel map shown in the figure are bused without being specified.The correspondence between each channel number and frequency is shown in Table 1. The reason why we did not designate the adjacent channels in order, 1st, 2nd, etc., but discretely every 5th channel, was to ensure that the difference in channel frequency used between each cordless terminal was sufficiently This is done to eliminate the possibility of interference by making it large.Of course, other methods of designation may be used as long as there are no duplicate designations.

Next, the operation after the initial routine is completed and normal operation begins, when a call is made from the cordless terminal to an outside line and when the cordless terminal receives a call from an outside line will be explained.

FIG. 7 shows a connection operation sequence when an outside line call is made from a cordless terminal.

Referring to the figure, when cordless handset 300 is first off-hook, a calling signal is transmitted from handset 300 to connection device 200. As already mentioned, when the call channel designation is completed for the handset 300 and the connection device 200, the channel to be used is set to the designated call channel. Therefore, all wireless communications, including the above-mentioned call signal, are performed using the above-mentioned designated communication channel from beginning to end, and the control channel is not used. In addition, before transmitting the above-mentioned call signal, it is confirmed whether the designated communication channel is not in a situation where it cannot be used, for example, because it is being used by another nearby system. Then, when it is confirmed that the device can be used, the above transmission is performed.

When the connecting device 200 receives the calling signal, if the identification number of the handset 300 included in the calling signal matches its own identification number in the EEPROM, the connecting device 200 responds to the received calling signal and calls the main device. It sends an off-hook signal to handset 100 and also sends a call response signal to handset 300. This call response signal also serves as an audio circuit on signal, and the handset 300 that receives this signal turns on the audio circuit. In addition, the main device 100 that received the off-hook signal sends an extension dial tone to the connection device 200, and the connection device 200 transmits this to the slave device 300.
Send to.

When the user hears an extension dial tone from the handset 54, the handset 300 dials a predetermined number for making an outside call (for example, "0").
). Then, a dial signal with the number “0” is sent to the connection device 200, and the connection device 200 sends the corresponding dial data “0” to the main device 100. In the main device 100, the control unit 15 receives this dial data "0", recognizes it as an outside line access request, and controls the outside line interface circuit 10 to capture a vacant office line (for example, 1) (close the DC loop). ) and control the call switching circuit 12 to acquire the outside line interface 10 of the central office line.
and the EKT interface 13 of the calling terminal.

When the central office exchange detects the capture, it sends a dial tone (outside line dial tone) to the central office line.

This dial tone is transmitted from the main device 100 to the connecting device 200.
The data is transmitted to the slave unit 300 via. When the user hears this outside dial tone, the user then dials the destination number. A dial signal for that number is transmitted from the handset 300,
In response to this, the connecting device 200 sends the corresponding dial data to the main device 100, and the main device 100 sends the corresponding selection signal to the central office line 1 in the form of a dial pulse or MF multiplied signal.

When the call ends, handset 300 goes on-hook and a call end signal is sent to connection device 200. The connection device 200 receives the call termination signal and sends an on-hook signal to the main device 100.
In response to this, the main device 100 opens the DC loop of the central office line 1, and the call ends.

Next, referring to FIG. 8, the connection operation when an outside line call is received to the cordless terminal will be explained.

The calling signal from the central office exchange is, for example, a 16 Hz AC signal, and is repeatedly sent to the main device 100 intermittently. In response to the first call signal, the main device 100 connects the connecting device 200 to
Send incoming commands to. The cordless terminal before receiving a call is in a standby state, and in this state, the connection device 200 connects to the receiving circuit 3.
8 is on, and the transmitting circuit 34 is off. When receiving an incoming command in this state, the connecting device 200 sends the transmitting circuit 3
4 and transmits an incoming signal to the handset 300.

All wireless communications, including the transmission of this incoming signal, are performed using the designated communication channel from beginning to end, and the control channel is not used. In addition, before transmitting the above incoming call signal, it is checked whether the specified call channel is unusable as mentioned above, and if it is confirmed that it can be used, it will be sent. will be held.

In the standby state, the handset 300 turns off the transmitting circuit 57 and turns on the receiving circuit 53 intermittently (for example, off for 2 seconds and on for 60 milliseconds). If an electric field is detected when the receiving circuit 53 is turned on, the on state is continued, and when receiving the above-mentioned incoming signal at this time, the handset 300 returns an incoming call response signal to the connecting device 200.

Thereafter, a ringtone command is sent from the main device 100 to the connection device 200 each time a ringing signal arrives, and when the connection device 200 receives an incoming call response signal from the slave device 300, it responds to the ringtone command and sends an incoming ringing command. is transmitted to the slave unit 300. Handset 300 makes a ringing sound (bell sound) from sounder 63 in response to this incoming ringing signal. The connection device 200 sends a ringtone command to the handset 300 until the handset 300 goes off-hook.

When the handset 300 goes off-hook, it sends off-hook data to the connection device 200, and the connection device 200 sends an off-hook signal to the main device 100 in response. Main device 100
When it receives an off-hook signal, it seizes the office line 1, connects the office line 1 and the cordless terminal, and starts a call.

The sequence for ending a call is the same as for making a call.

As described above, since each cordless terminal performs wireless communication by using its designated communication channel throughout so as not to overlap with each other, it is possible for a plurality of cordless terminals to make or receive calls at the same time. Furthermore, since the conventional procedure for switching the used channel from a control channel to a communication channel when starting wireless communication is no longer necessary, the time from the start of an outgoing/incoming call to the completion of a connection is shortened.

By the way, if the specified communication channel becomes unavailable due to, for example, being already used by another nearby system, the user is prohibited from making a call or receiving an incoming call. In this case, the user presses the call channel clear button 44.61 on the handset 300 and the connection device 200.

Then, both handset 300 and connection device 200 are returned to the state before the communication channel was designated, and connection device 200 notifies main device 100 of this fact. As a result, the above-described communication channel designation sequence is executed once again for that terminal, and the used channel is changed to the newly designated communication channel.

Although the above explanation has been made using a key telephone system as an example, the present invention can be widely applied to other systems such as a home telephone system and a PBX system.

〔Effect of the invention〕

As explained above, according to the present invention, a different wireless channel is specified for each cordless terminal, and each terminal uses the specified wireless channel exclusively, so that multiple terminals can use the same wireless channel. Therefore, multiple terminals can make or receive calls simultaneously.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the main device of a key telephone system to which an embodiment of the present invention is applied, FIG. 2 is a block diagram showing the configuration of a connecting device for a cordless terminal of the same system, and FIG. 3 is a block diagram showing the configuration of a handset of a cordless terminal in the same system, FIG. 4 is a diagram showing a sequence of call channel designation in the same system, and FIG. 5 is an example of a table formed in the RAM 16 in FIG. 1. A diagram showing
Fig. 6 is a diagram showing the selection order of call channels in the same system, Fig. 7 is a diagram showing the connection operation sequence when making an outside call from a cordless terminal in the same system, and Fig. 8 is a diagram showing the sequence of connection operations to a cordless terminal in the same system. Figure 9 is a block diagram showing the general system configuration of a key telephone system having a cordless terminal; Figure 10 is a diagram showing the connection operation sequence when an outside line call is received; Figure 10 is a diagram showing the connection operation sequence when an outside line call is received; Figure 10 is a block diagram showing the general system configuration of a key telephone system having a cordless terminal; Figure 11 is a diagram showing the connection operation sequence when a call is made, Figure 11 is a diagram showing the connection operation sequence when an outside line call is received to a cordless terminal in a conventional system, and Figure 12 is a diagram showing the connection operation sequence when an outside line call is received to a cordless terminal in the conventional system. A time chart illustrating the operation, FIG. 13, is a diagram for explaining the problem when calls arrive at two cordless terminals at the same time in the conventional system. 100...Main unit (KSU), 200...Connection device (CE), 300...Cordless slave unit (installed), 1
0...External line interface circuit, 12...Telephone exchange circuit, 13.14...EKT interface circuit, 1
5... Control unit, 16... RAM, 31... Receiving circuit, 32... Transmitting circuit, 34... Transmitting circuit (T
), 35.39...PLL circuit, 38...Receiving circuit (RX), 36...Control unit, 42...Data interface circuit, 43...EEPROM, 44...Speech channel clear switch , 51...Reception circuit (RX
), 52.58... PLL circuit, 53... Receiving circuit, 54... Receiver, 55... Transmitter, 56...
Transmission circuit, 57... Transmission circuit (TX), 59...
Control unit, 60...EEPROM. 61... Call channel clear switch, 68... Dial and function button, 69... Hook button. Figure 1

Claims (1)

[Claims] 1. A method for setting a wireless channel to be used by each cordless terminal in a telephone system having a center and a plurality of cordless terminals communicatively connected to the center, comprising: a step of selecting wireless channels to be used by each of the cordless terminals from a predetermined group of wireless channels so as not to overlap with each other, and notifying each of the selected wireless channels from the center to each of the cordless terminals; and a step of storing the notified wireless channel in each cordless terminal and using the stored wireless channel. 2. A device for setting a wireless channel to be used by each cordless terminal in a telephone system having a center and a plurality of cordless terminals communicably connected to the center, wherein the center sets a wireless channel in a predetermined group of wireless channels. channel selection means for selecting radio channels to be used by each of the cordless terminals so as not to overlap with each other; and channel specification means for notifying each of the selected radio channels from the center to each of the cordless terminals. , Channel storage means for storing the notified wireless channel in each cordless terminal, and channel control means for making the wireless channel to be used match the stored wireless channel in each cordless terminal. Wireless channel setting device. 3. The apparatus according to claim 2, wherein each cordless terminal investigates the availability/usage status of each channel of the predetermined wireless channel group to obtain local vacant channel information, and notifies the center of this information. The channel selection means further includes local empty channel information checking means, and the channel selection means selects each terminal from among the wireless channels indicated as empty by the local empty channel information from each terminal in the predetermined group of wireless channels. A wireless channel setting device that selects a wireless channel to be used. 4. The apparatus according to claim 2, wherein the channel selection means selects radio channels that are not close to each other from the predetermined group of radio channels as radio channels to be used by each cordless terminal. Wireless channel setting device. 5. The apparatus according to claim 2, further comprising: channel clearing means for erasing the wireless channel stored in the selected cordless terminal in order to change the wireless channel used by the selected cordless terminal; changing channel selection for selecting a new wireless channel from the predetermined wireless channel group that is different from the erased wireless channel and any of the wireless channels stored in other cordless terminals in response to the operation of the clearing means; and change channel specifying means for notifying the selected cordless terminal of the selected new wireless channel, and the channel storage means stores the notified new wireless channel and stores the new wireless channel. The wireless channel setting device is characterized in that the selected cordless terminal uses the new wireless channel thereafter.