JPH01225269A - Cordless telephone - Google Patents

Abstract

PURPOSE:To shorten a connecting time at the time of recalling by opening a channel between a hand set and a base unit during a prescribed period even when the hand set side executes off-hook operation. CONSTITUTION:When talking is finished and a talk key 152 of a hand set 1 is caused to be a standby mode, a relay contact in the base unit side is turned off and connection with a telephone line goes to an on-hook condition. However, during a prescribed time after the talk key 152 of the hand set 1 is caused to be the standby mode, by the control of a control circuit 140, the transmitting and receiving of signals Su and Sd is continued and the channel between the hand set 1 and base unit is left open. Accordingly, when telephone calls are continuously executed to plural opponents or redialing is executed, without opening the channel, dialing can be executed speedily.

Description

[Detailed description of the invention] The explanation will be given in the following order.

A. Industrial application field B. Summary of the invention C Conventional technology l) Problems to be solved by the invention E! Measures and actions to solve 1191 G Example G1 first embodiment (Figures 1 to 5) G2 other examples Effect of H invention 8. Industrial application fields This invention relates to cordless telephones.

B. Summary of the Invention This invention provides a method for re-calling a cordless telephone by keeping the channel open between the handset and the base unit for a predetermined period even if the handset performs an on-hook operation. This is designed to shorten the connection time.

C. Prior Art In countries such as Japan and the United States, a telephone system called a cordless telephone is being considered.

As shown in Fig. 6, it is composed of a transceiver (1) called a handset and a transceiver (2) called a base unit, and a telephone line (3) is connected to the base unit (2). together with the base unit (2
) and the handset (1) are coupled by radio waves,
A call from a subscriber is answered using the handset (l) in the same way as a general telephone.

Therefore, the subscriber can freely move the handset (11) when making a call, and can use the telephone, for example, outdoors, without the telephone cord becoming tangled or getting in the way.

Note that the distance that the handset (1) can be separated from the base unit (2), that is, the service area is:
It is about 300m. In addition, the frequency of radio waves used between the handset (11) and the base unit (2) is
In the case of Japan, the upstream channel is in the 49 MHz band, the down channel is in the 46 MHz band, and 10 duplex channels are permitted.

Thus, this cordless telephone allows the telephone to be used conveniently.

By the way, in such cordless telephones,
The handset (-1) is provided with a switch called a talk switch, and when this switch is switched to a standby contact, only the receiving circuit is working and waiting for a call from the base unit (2). When the talk switch is switched to the talk contact, the transmitter circuit also operates to call the base unit (2).Also, the base unit (2) does not have a switch like the talk switch (as usual). Only the receiving circuit works and when there is a call from the handset (2), or when there is an incoming call from the telephone line, the transmitting circuit also works and the communication between the handset (1) and the base unit (2) is carried out through radio waves. Linked.

Then, when the call is finished, the talk switch on the handset (1) may be switched to the standby contact.

However, since the base unit (2) does not have a switch such as a talk switch, methods of using a guard tone signal or a termination code have been considered as methods for performing call termination processing in the base unit (2).

In other words, during a call, the handset (1) continuously transmits a guard tone signal at a frequency of 4 kHz, for example, outside the voice band, to the base unit (2) at the same time as the voice signal. When this guard tone signal is no longer obtained, it is assumed that the call has ended, the call is terminated, and the call enters standby mode.

In addition, when the latter switches the talk switch of the handset (1) to the standby contact, the handset (1)
transmits a call termination code to the base unit (2), and when the base unit (2) receives this, the base unit (2) performs call termination processing and enters standby mode.

However, with either method, even if the other party hangs up before switching the talk switch on the handset (1) to the standby contact, this cannot be detected by the base unit, so in the end, the handset (1) switches the talk switch to the standby contact. When switching to the standby contact, the call termination process is performed as described above.

Document: Specification and drawing D of Japanese Patent Application No. 174397/1983
Problem to be Solved by the Invention By the way, in any case of call termination processing, when the call termination processing is performed, the handset (1) and the base unit (2)
) is stopped and the channel between the hand cent (1) and the base unit (2) is closed.

Further, in the base unit (2), a relay contact corresponding to a hook switch of a general telephone is turned off, and the telephone line (3) is opened.

Therefore, for example, if you finish a call with one party and then call the next party, or if you make a mistake in dialing the number and dial again, in other words, if you try to call again within a short period of time, , First, switch the talk switch to the standby contact, close the channel between the handset (1) and the base unit (2) by the above-mentioned call termination process, and temporarily release the line (3).
Next, switch the talk switch to the talk contact to open the channel with the base unit (2) again, and
A connection with line (3) will be made.

However, in this case, the PLL of each transmitting circuit of the handset (1) and base unit (2) will temporarily stop oscillating and then start oscillating again, and when this oscillation starts, the PLL will start up. It may take some time for the handset (1) and base unit (2) to find a free channel.

This invention attempts to solve these problems.

E Means for Solving the Problems Therefore, the present invention includes a base unit connected to a telephone line and a handset paired with this base unit, and when making a call, the handset and base unit are connected to each other. In a cordless telephone connected by a channel using radio waves, when a switch indicating the end of a call is operated on the handset during the above call, the operation of the switch is notified to the base unit through the channel. transmitted to,
In the base unit, when the operation of the switch is transmitted through the channel, the base unit is controlled to be on-hook to the telephone line, and from the time when the switch is operated. The cordless telephone is configured to close the channel after a predetermined period of time.

F Effect Even if the handset performs an on-hook operation, the re-call will be accepted immediately.

G. Embodiment FIG. 1 shows an example of a handset (1), (110)
is a transmitting circuit, and (120) is a receiving circuit. Also, 98
Figure 2 shows an example of the base unit (2), (210)
is a transmitting circuit, and (220) is a receiving circuit.

When transmitting a call, in the handset (1), the audio signal St from the transmitter (111) is passed through the PLL signal line from the low frequency amplifier (112) to the low pass filter (113) to the adder circuit (114). (115) v
CO (not shown) and is converted into an up channel FM signal Su, and this FM signal Su is passed through a band pass filter (116
) → High frequency power amplifier (117) → Duplexer (1
18) to the antenna (100) and transmitted to the base unit (2).

Then, in the base unit (2), the signal (radio wave) Su from the handset (1) is sent to the antenna (2G0).
The received signal Su is received by the duplexer (
21B) → High frequency amplifier (221) - Bandpass filter (222) with all upstream channels as passband
A local oscillation signal of a predetermined frequency from the PLL (224) is supplied to the mixer circuit (223) to generate the signal S.
u is converted into an intermediate frequency signal, and this intermediate frequency signal passes through an intermediate frequency amplifier (225) to an FM demodulation circuit (226).
is supplied to the audio signal St, and the audio signal St is tuned to fm, and this signal St
However, the low frequency amplifier (227) → 2-wire/4-wire conversion circuit (2
31) - sent to the telephone line (3) through the signal line of the relay contact (232).

Also, when receiving a call, the voice signal Sr from the telephone line (3)
However, the handset (1) receives the call 1! using the same process as when sending a call. (12B). That is, line (3)
The audio signal Sr from P L L (215) (D V CO (not shown) and is converted into a down channel FM signal Sd which becomes an up FM signal S color pair, and this signal Sd is
The antenna (
200) and transmitted to the handset (1).

In the handset +1), the signal Sd from the base unit (2) is received by the antenna (100), and the received signal Sd is sent to the duplexer (11B).
→ High frequency amplifier (121) → High frequency amplifier (121) The oscillation signal is supplied to the mixer circuit (123) and the signal Sd is converted into an intermediate frequency signal, and this intermediate frequency signal is supplied to the intermediate station amplifier (123).
25) to FMfj [11 circuits < 126), where the audio signal Sr is demodulated, and this signal Sr is supplied to the receiver (12B) through a low frequency amplifier (127).

Further, in the handset (11), (140) indicates a control circuit for i-controlling communication channels and the like.

This control circuit (140) is composed of an l-chip type microcomputer, and (141)
For example, a CPU with 4-bit parallel processing.

(142) is the ROM in which the program is written, (
143) is a RAM for a work area, (144) is an input port, and (145) is an output port. In addition, R.U.M.
(142) is also provided with a routine (300'') of the flowchart shown in FIG. 4, for example.

Furthermore, the microcomputer (140) has a dial key (15).
1), l-key (152), mode key (1
53) is connected. In this case, dial key (151
) is a non-lock type button switch for entering the other party's phone number. Also, talk key (15
2) and the mode key (153) are switches for changing the operating mode of the handset (1), the talk key (152) is a non-lock type button switch, and the mode key (153) is a lock type slide switch. .

Each time the talk key (152) is pressed, a channel is opened between the base unit (2) and a call can be made in "talk mode", and the channel is closed and the standby mode is set to "standby mode". mode can be switched alternately. In this standby mode, if the mode key (153) is in "normal mode" (the state shown in the figure), it will stand by for calls from the handset (+1) or incoming calls from outside lines, and the mode key (153) 153)
is in "save mode" (opposite to the picture!!),
It waits only for calls originating from the handset (1), and ignores incoming calls from outside lines.

In other words, when the mode key (153) is in normal mode, you can make and receive calls like a regular cordless telephone or telephone, but when it is in save mode,
It will be used only for making calls. Then, no matter which mode the mode key (153) is in, if you press the talk key (152),
You can talk in talk mode and press the talk key (152
) again, the device waits in the pre-call mode indicated by the mode key (153).

Further, (154) indicates a RAM, in which an identification code ID, which will be described later, is stored and, although not shown, the power supply number 1 is backed up.

Further, (161) indicates an encoder, which is controlled by the microcomputer (140) and receives the command signal CMN required by the handset (1) and the base unit (2).
It forms O.

FIG. 3 shows an example of the signal format of the command signal CMNO, which has a bit synchronization signal BSYN of 12 or more bits, in this example 16 bits, at the beginning.
This is followed by a 16-bit frame synchronization signal FSYN. In this case, these signals BSYN and PSYN are, for example, BSYN-“0IOIOIQIOIOIOIOI”)
'5YN-"1100010011010110"...
・・1'5YN-1001001100110110" for upstream channel...
...has a specific bit pattern indicated by the lower rechan function.

Further, the four-mantle signal CMND includes, following the signal FSYN, a 25-bit identification code 10 for identifying the handset I-(1) and the base unit (2), and a 12-bit error code for this identification code ID. Correction code EC
C in order, and the code ECC is followed by the control code CT)? It has L. This control code CTRL is a code that controls the opening/closing of a channel between the handset +1) and the base unit (2), a code that transmits the telephone number of the other party when making a call, and a code that indicates the telephone number, etc. When opening a channel, the control contents are the data of the first bit pattern, and when the telephone number of the other party is called, it is the data of the second bit pattern and the data of the telephone number. The data of the bit pattern shown (opcode) and the data necessary for the control content (operand. This may be unnecessary.
For example, when it is a call end code).

Note that in this command signal CMNO, the synchronization signal B
SYN and FSYN are NRZ signals, but identification code 10 to control code CTRL are split phase signals (Manchester code) converted from NRZ signals. Also, the transmission speed of signal CMNo is, for example, 1200.
bps.

When this command signal CFINO is formed, it passes through the adder circuit (114) to ptt, (115
), thus the signal Su is supplied to the command signal C
FM change 11 (FSK) is performed by MND.

Further, (162) indicates a squelch detection circuit, which is connected to the intermediate frequency amplifier (125) and detects the presence or absence of the FM signal Sd from the level of the intermediate frequency signal. ).

Furthermore, (163) indicates a decoder, which corresponds to the encoder (161) and is connected to the demodulation circuit (126) to extract the command signal CMNO sent from the base unit (2). The extracted signal side ND is supplied to the microcomputer (140).

Further, (165) indicates a ring tone signal forming circuit,
This is controlled by a microcomputer (140) to generate a ring tone signal when a call is received, and the ring tone signal is supplied to a ringer speaker (166).

Further, from the microcomputer (140), signals CHNL specifying channels are sent to PLL (115), (12
4), and a signal TXEN for controlling whether or not to send out the FM signal Su is also supplied to the PLL (115). Also, from the icon (140), the miniting signal MUTI! is the amplifier (112), (127
).

Further, (167) indicates an LED, and (168) indicates an LED unit, whose lighting is controlled by the microcomputer (140), and the LED (167) is lit in the talk mode. Further, the LED unit (16B) is a display in which, for example, 10 LEDs are arranged in a row, and this is lit according to the channel, dial key input, etc.

Further, in the base unit (2), (240) indicates a control circuit, and this control circuit (240) is configured similarly to the control circuit (140) of the handset (1) and has the same functions. , the circuits corresponding to circuits t141) to (145) of the control circuit (140) include 10
A code in the 200s will be used instead of a code in the 0s, and the explanation will be omitted. However, the ROM (242) is provided with a routine (400) shown in FIG. 5, for example.

Also, RAM (254) and circuits (281) to (263)
) also includes the RAM (154) and circuit (
161) to (163), and the same applies to each signal, so a description thereof will also be omitted.

Furthermore, (265) indicates a dial signal forming circuit, which is controlled by the microcomputer (240) and forms a tone encoded signal (DTMF signal) TBNC corresponding to the telephone number when making a call to the other party. The signal TENC is supplied to an amplifier (227).

Also, (266) indicates a relay, which is an amplifier (266).
7) is controlled by a microcomputer (240), and the relay contact is a contact (232);
(268) indicates a ring tone signal detection circuit, which is connected to the telephone line (3) and detects a ring tone signal when an incoming call is received, and the detection signal RG
TN is supplied to the microcomputer (240).

And the handset (1) and base unit (2)
, the following processing is performed by the CPUs (141) and (241) according to routines (300) and (400). In the following description, for the sake of simplicity, the talk key (152) is assumed to be a lock type switch that can be switched between a talk mode contact and a standby mode contact.

That is, in the hand sent (1), in the standby mode, the PLLs (115) and (124) are controlled by the signal CHNL in step (301) and set to the upstream and downstream channels corresponding to the value of the signal CHNL, and the next In step (302), the switching position of the talk key (152) is checked, and in this case it is connected to the standby mode contact.
The process proceeds from step (302) to step (303), and in this step (303), the switching position of the mode key (153) is checked, and when the mode is normal mode, the process proceeds from step (303) to step (304). ), and in this step (304), it is checked by the signal 5QLC whether the FM signal Sd is received on the downlink channel set in step (301), and when the signal Sd is not received, the process proceeds to step (304). 304) to step (3
05), and in this step (305) the signal C
HNL is set to the value of the next channel (adjacent channel), and then the process returns to step (301).

Further, when the signal Sd is received in step (304), the process proceeds from step (304) to step (306), and in this step (306), the identification information included in the command signal SMNI) from the decoder (163) is It is checked whether the code ID and the identification code ID of the RAM (154) match, and if they do not match (this is from the base unit (2) of another subscriber), the process starts from step (306). Step (30
Proceed to 5).

Furthermore, in step (303), the mode key (1
53) is in standby mode, the process returns from step (303) to step (3G2).

Therefore, in the handset (1), in the standby mode, if the mode key' (153) is the normal mode, steps (301) to (306) are repeated and all the downlink channels are repeatedly scanned in order. When the key power of the talk key (152) is checked and the mode key (153) is in standby mode, the talk key (152) is activated in step (302).
Only the key personnel of 2) are checked.

Also, in base unit cutting), during standby, steps (401) and (402) of routine (400)
.

(404) to (406) are executed. In this case, these steps (401), (404) to (406)
are steps (301), (304) to (306)
It performs the same processing as , so the explanation will be omitted. Then, in step (402), the detection signal RGTN
detects the presence or absence of an incoming call from outside line (3), and if there is no incoming call, the process moves from step (402) to step (
Proceed to step 404), and in step <404),
In place of checking the presence or absence of the FM signal Sd in step (303), the presence or absence of the FM signal Su is checked.

Therefore, in the base unit (2), steps (401) to (406) are repeated during standby, all uplink channels are repeatedly scanned in order, and incoming calls from outside lines are checked. .

When the handset (1) makes a call, the talk switch (152) is switched to the talk mode.

Then, this is determined in step (302),
The process proceeds from step (302) to step (311), and in this step (311), step (30
It is checked by signal 5QLC whether the uplink and downlink channels set in step 1) are being used by another station, and if they are not being used, the process proceeds from step (311') to step (312), and In this step (312) the signal TXI! Sending of the FM signal Su is permitted by N, and then in step (313) the identification code I is sent from the RAM (154).
D is extracted and supplied to the encoder (161), and a control code CTRL indicating a call is sent to the microcomputer (161).
40) to an encoder (161), and a command signal CMND whose control code CTRL is a calling code is taken out from the encoder (161).
NO is supplied to the adder circuit (114). therefore,
This command signal CI'lNO causes step (301)
It is transmitted to the base unit (2) using the upstream channel FM signal Su set at .

In this case, the command signal C in step (313)
The transmission of llN0 is repeated over a period of at least one channel scan in the base unit (2), assuming that there is no response from the base unit (z) (21).

While the base unit (2) is on standby, steps (401) to (406) are repeated to sequentially scan all uplink channels.
When the upstream channel transmitting the signal CMND is reached, the process proceeds from step (404) to step (406), the scan is stopped, and the identification code ID in the signal CMND is determined.

In this case, the identification code 10 is the RAM
(254) identification code! Since it matches D, the process proceeds from step (406) to step (421), and in this step (421), the signal TX15N causes the FM
Transmission of the signal Sd is permitted, and then in step (422), a command signal CFlNO is formed in the same manner as in step (313), and this command signal CNID is
The FM signal "Sd" of the downlink channel paired with the uplink channel set in step (301) is returned to the handset (1). However, in this case, the control code CT in the returned command signal CMND
RL is a call confirmation code indicating that a call code (control code CTRL) has been received from the handset (1).

Then, the process starts from step (422) to step (43).
1), in this step <431), the relay (262) is driven to connect the conversion circuit (231) and the line (3) through its contact (232), and then in step (432) the signal MITI ! This releases the miniting of the amplifiers (212) and (227). ' Also, in handset (1), step (31
At the same time as the command signal CMNO is transmitted in step 3), the output signal of the decoder (163) is checked to see if the identification code 10 has been returned in step (314) (actually, step (313)
and (314) are performed alternately in a time-sharing manner until the channel scan in the base unit (2) completes one cycle or until the return of the identification code ID is confirmed).

And in this case, the base unit (2) is the identification code! Having returned D, the process proceeds from step (314) to step (332) in which the channel between the handset ('l) and the base unit (2) is connected, i.e., the handset ('l) is connected. In 1), the signal MUTI! Amplifier (11
2).

Mining of (127) is canceled.

Therefore, the handset (1) has a base unit (
This means that it is connected to the telephone line (3) through 2).

Therefore, in the handset (1), the dial key (1)
51) corresponding to the telephone number of the other party, the encoder (161) extracts a code indicating that the control code CTRL is a telephone number and a command signal CMND which is the data of the telephone number. Signal CI
'lNO is sent to the base unit (2:

In the base unit (2), the decoder (
A command signal CMID is taken out from CMND (263), and a forming circuit (265) is controlled by a microcomputer (24G) based on a control code CTRL in this signal/CMND to generate a tone encoded signal Tf! corresponding to the telephone number of the other party.
NC is formed and this signal T[! NC is amplifier (227
), and further converter circuit (231) and relay contact (
232) to the telephone line (3). Therefore, this signal Tl! The other party is called by NC,
If the other party answers the call, the call can be made as described above.

Note that in step (311), step (301)
) is already in use by another station, the process proceeds from step (311) to step (305);
As a result, the signal CHNL is set to the value of the next channel, and the process returns to step (301). Therefore, step (312
) ~ (314), (421).

The process (422) will be performed on an empty channel, and subsequent calls will be made on that empty channel.

Further, in step (314), the base unit (
If the correct identification code ID is not returned from step 2), the process proceeds from step 314 to step 3.
15), and in this step (315) the signal T
XI! The transmission of the signal Su is stopped by H, and the process then proceeds to step (305). Therefore, when the identification code ID is not returned from the base unit (2), the base unit (2) is transmitted in the same way on the next free channel.
) is called.

In this way, when the handset (1) makes a call, when the talk switch (152) is set to talk mode, an empty channel is searched, the base unit (2) is called on that empty channel, and the base unit (2) responds. , handset (1) and base unit (2)
A channel is opened between the relay contacts (
232) is turned on and becomes ready to call and talk to the other party.

Further, when there is an incoming call from the telephone line (3), steps (411) to (415) of the routine (400) and steps (321), (
322) is executed. In this case, these steps (4
11) - (415) and (321), (322)
is steps (311) to (315) and (421)
, (422), and when there is an incoming call, the signal RGTN is determined in step (402), so the process proceeds from step (402) to step (411). Similarly, connect the telephone line (3
) connects the handset (1) through the base unit (2).
connected to.

When the handset (1) and the base unit (2) are connected and a call is being made by making a call from the handset (1) or by receiving a call from the telephone line (3), the handset (1) In this case, the process proceeds from step (332) to step (341), and in this step (341), the talk switch (152) is checked, and when it is in the talk mode, the process (341)
Return to Therefore, during a call, always use the talk switch (1).
52) is being monitored.

Then, when you finish the call, press the talk switch (152
) is switched to standby mode, this is determined in step (341), and the process proceeds to step (341).
Proceed to step (342) from this step (342).
), the signal TE causes an amplifier (112),
(127) is minified, and a call termination code indicating the end of the call is supplied from the microcomputer (140) to the encoder (161), and the encoder (161) receives the call termination code as a control code CTRL. A command signal CMNO is output, and this is transmitted to the base unit (2) by the FM signal Su.

Subsequently, the process proceeds to step (343), where the software-based timer HTI'lR is reset to "0", and then proceeds to step (344), where this step (344
), the timer HTMR is activated for a predetermined period τ (for example, τ
is within a few seconds), and the HTM
When R≦τ, the process proceeds from step (344) to step (345), and in this step (345), the mode of the talk key (152) is checked, and when it is in standby mode, the process proceeds from step (345) to step (345). The process advances to (346), where the timer HTMR is incremented, and then the process returns to step (344).

Therefore, when the call ends, ε ~ talk key (15
When 2) is set to standby mode, steps (344) to (346) are repeated after the call termination code is sent, and the timer HTMR is incremented.At this time, the FM signal Su is not yet transmitted. It remains as it is.

And this timer HT? When IR becomes )ITMR>τ, this is determined in step (344), and the process proceeds from step (344) to step (348), where the transmission of the FM signal Su is stopped by the signal TXEN. , then the processing is step (
Return to 301). Therefore, even if you end the call and put the talk key (152) into standby mode, the period τ is F.
The transmission of the M signal Su continues, ie the upstream channel remains open, and after the period τ the upstream channel is closed and enters standby mode.

However, before the period τ has elapsed, if the mode key (152) is placed in talk mode again, this is the step (345).
The process proceeds from step (345) to step (347), and in step (347), the amplifier (112), (
127) is released, and the control code CTl? Command signal C? with calling code as L? IND is retrieved from the encoder (181),
This is FM Shin! It is transmitted by Su to the base unit (2), and then the process returns to step (341). Therefore, even if the call ends and the mode key (152) is set to standby mode, if the mode key (152) is set to talk mode within the period τ, the transmission of the FM signal Su will not be stopped and the call will be made again. .

On the other hand, in the base unit (2), while a telephone call is being made, the process starts from step (432) to step <
441), and in this step (441), the control code CTRL of the command signal CMNO from the decoder (262) is checked, and this control code CTRL
If no call termination code has been sent, the process returns to step (441). Therefore, during a call, the presence or absence of a call termination code from the handset (1) is constantly checked.

Then, end the call and go to step (342).When the call end code is sent from 2, this is taken to step (441).
The process proceeds from step (441) to step (442), and in step (442), the relay contact (232) is turned off, that is, the ordinary telephone is placed in an on-hook state.

Subsequently, the process proceeds to step (443) where the timer BTMR is reset to rOJ by software, and then proceeds to step (444), where it is checked whether the timer BTMR is within the period τ, BTMR:! When ar, the process proceeds from step (444) to step (445), and in this step (445), it is checked whether or not a calling code can be obtained from the decoder (263) as the control code CTRL, and if not, the process proceeds to step (445). , processing is step <
445), proceed to step (446) and set the timer BTM.
After R is incremented, the process returns to step (444).

Therefore, the talk key (152
) in standby mode, the relay contact (232)
After the timer BT? is turned off, steps <444) to (446) are repeated, and the timer BT? IR is incremented. At this time, FM message! sd is still being transmitted.

When the timer BTMR becomes BTMR>τ, this is determined in step (444), and the process proceeds from step (444) to step (448), where the signal ↑Xf! F by H
Transmission of the M signal Sd is stopped, and the process then proceeds to step (4).
Return to 01). Therefore, when the call is ended and the talk key (152) is placed in standby mode, the base unit (2) is in the on-hook state, but the transmission of the FM signal Sd continues for the period τ, that is, the downlink channel is not opened. After the period τ has passed, its downstream channel will be closed and it will enter standby mode.

However, if the mode key (152) is set to the talk mode again before the period τ has passed, a calling code is transmitted as the control code CTRL in step (347), and this is determined in step <445).
The process proceeds from step (445) to step (447), and in this step (447), the signal MtlTH
k: Yori 777” (212), (L!27)
The relay contact (232) is turned on as the notification is released, and the process then proceeds to step (44).
Return to 1). Therefore, when the call ends and the mode key (
Even if the mode key (152) is set to standby mode, if the mode key (152) is set to talk mode within period 1, the FM signal S
The transmission of d is not stopped and the base unit (2) is left on-hook.

Thus, according to the present invention, it is possible to make a telephone call using a cordless telephone, but in this case, especially according to the present invention, when the telephone call ends, the talk key (152) of the handset (1) is pressed into the stampy mode, Then,
The relay contact (232) of the base unit (2) is turned off and the connection with the telephone line (3) is on-hook, but after setting the talk key (152) of the handset (1) to standby mode, During the period τ, for example, several seconds, the transmission and reception of the FM signals Su and Sd continues, and the channel between the hand base (1) and the base unit (2) remains open, so that multiple parties can The time required to open a channel between the handbase (1) and the base unit (2) in the case of repeated calls within a short period of time, such as when making consecutive calls or re-dialing. You can dial immediately without the need for

G2 Other Actual htit Examples In the above, the process when the talk key (152) is operated can also be performed by an interrupt. Furthermore, when the command signal CMND is transmitted in steps (342) and (347), step (422)
) indicating that the reception of the command signal CMND has been confirmed from the base unit (2).
It is also possible to return NO and perform the subsequent processing when this command signal CMND is returned.

Furthermore, the telephone number of the other party can also be sent out by means of a dial pulse.

H Effects of the Invention According to this invention, when a call ends, when the talk key (152) of the handset 11) is set to standby mode, the relay contact (232) of the base unit (2) is turned off and the telephone line ( 3) is in an on-hook state, but the talk key (152
) for a predetermined period τ, e.g., several seconds, after the handbase (1) and the base unit (2) are placed in standby mode, the transmission and reception of the FM signal S u IS d continues and the channel between the handbase (1) and the base unit (2) remains open. Therefore, when making a call again within a short period of time, such as when calling multiple parties in succession or re-dialing, the hand base (1) and base unit ( 2) You can dial immediately without needing time to open a channel between calls.

[Brief explanation of the drawing]

FIGS. 1 and 2 are system diagrams of an example of the present invention, and FIGS. 3 to 6 are diagrams for explaining the same. (1) is the handset, (2) is the base unit, (1)
10). (210) is a transmitting circuit, (120), (220)
is the receiving circuit, (140), (240) is the circuit a circuit. 1! Figure 6 Flow Yard Figure 4 B Figure 5 B

Claims (1)

[Claims] The device includes a base unit connected to a telephone line and a handset paired with the base unit, and during a call, the handset and the base unit are connected by a channel using radio waves. In the cordless telephone, when a switch indicating the end of the call is operated on the handset during the above call, the operation of the switch is transmitted to the base unit through the channel, and the base unit: When the operation of the switch is transmitted through the channel, the base unit is controlled to be on-hook for the telephone line, and after a predetermined period from when the switch was operated, the base unit is transmitted to the telephone line. A cordless telephone that closes.