JPH01200837A - Method for controlling communication in cordless telephone system and cordless telephone system using it - Google Patents

Abstract

PURPOSE:To keep sufficient privacy and to obtain prefetch priority form with one set of a transmission/reception frequency pair when plural handsets are made to correspond to a base unit by controlling a communication by using a transmission carrier existence signal, etc. CONSTITUTION:Plural handsets HS-1, HS-2... are provided corresponding to one base unit BU, and in a system where one set of transmission/reception frequency is given, the HS-1 allows a transmission carrier frequency fh to be an outgoing condition. In such a condition, for example, when a supervisory frequency switching signal Cs is outputted from a control circuit 11 of the HS-2 to a reception circuit 13, since the fh originated by the HS-1 exists already at an antenna 10, a transmission carrier existence signal Dx to indicate the existence of the carrier is outputted from the circuit 13. Consequently, the circuit 11 outputs a transmission permitting signal Sx to a transmission circuit 12 in adding a logical value to indicate the inhibition of transmission to the signal Sx, and a condition not to operate the circuit 12 is maintained. Thus, when the plural sets of HSs are made to correspond to one set of BU, even by one set of transmission/reception frequency pair, the sufficient privacy and prefetch priority form can be satisfied.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cordless telephone system, which is a type of communication system that utilizes full-duplex communication using an antenna.
In particular, the present invention relates to a communication control method when a plurality of handsets are made to correspond to one base unit connected to a telephone line, and a cordless telephone device used therefor.

[Prior Art] In order to be able to make calls to a telephone connected to a telephone line by wire without being restricted by the length of the connection cord,
A cordless telephone consists of a base unit, which corresponds to the main body of the telephone, and a handset (also called a remote unit or portable unit), which has a handset and a dial control part in one housing, and is connected via an antenna. Recently, it has become popular on the market.

This is particularly the case with regard to the use of weak radio waves of about 0.5 mW, which has been officially approved in a fairly liberal manner.
In any case, the conventional basic structural concept of such a cordless telephone system is as shown in the third diagram.

Generally, one handset H8 corresponds to one base unit 80, and the base unit BU is connected to a telephone line via a line connection circuit 33.

When there is a bell ringing from the telephone line side, the transmitting circuit 31 in the base unit BIJ puts a bell signal on its own transmission carrier frequency fb, sends it to the antenna, and sends it to the receiving circuit on the hand set H5 side. 42 receives and demodulates the signal, and then generates an audible bell sound from a dual-purpose or dedicated speaker or sounding body in the receiver 44.

Although not shown in this figure, the person who inquired about this ringing tone responds by picking up the handset and raising the hook switch on an ordinary telephone. When the response switch provided at the location is operated, the transmitter circuit 41 in the hand set H5 transmits a response signal to the antenna on a predetermined carrier frequency fh.

This response signal is sent to the receiving circuit 32 in the base unit BU.
When the line connection circuit 33 is activated and the line is connected, the base unit BU receives the frequency f.
Call information from the other party is sent using b as a carrier, and is provided from the receiver circuit 42 in the handset via the receiver 44, while the information input to the receiver 43 is transmitted from the handset HS side. After being modulated by a suitable modulation method by the circuit 41, it is sent to the base unit BU side using the frequency fh as a transmission carrier.

This kind of full-duplex communication operation is also performed when a call is made by pressing a button (dial operation) from the handset HS side, but normally such full-duplex communication is performed. Therefore, a pair of transmitting and receiving frequencies fb and fh, each set as a carrier, is also called a "channel bare" or "duplex bear".

However, recently, there have been requests to make the -white base unit BU compatible with a plurality of handsets H5, like so-called parent-child telephones in wired telephones.

It is true that such a system is extremely convenient, for example because it allows each family member to place a handset in a convenient place within each household. Sufficient countermeasures must be taken to prevent call collisions between sets, that is, mutual interference, and in particular, in order to place importance on confidentiality, a so-called "preemption priority" system must be implemented.

In other words, only the handset that operates the answer switch after hearing the ring tone will be enabled; any handset that operates the answer switch after that will be disabled; It only enables the handset and disables the others.

Therefore, what has traditionally been considered to be convenient for such control is the adoption of a so-called multi-channel access method, abbreviated as MCA.

In other words, the transmitting and receiving frequency pair fh in the previous full-duplex communication
, fb with different frequencies and prepared as many as the number of handsets to provide multiple channels.

If there are m (≧2) handsets, the transmitting and receiving frequency pairs are fb-1+fh-1; fb-2+fh-2;...
...; Prepare a set (m channels) of non-overlapping frequency pairs such as fb-m + fh-m, and when a bell signal is received when no call is generated from any handset, , all transmission frequencies fb-1+ fb-2+...+ in order from the base unit side.
A bell signal is placed on fb-s, and on the other hand, the total frequency fh-1+ fh- which is the transmission frequency from each handset side and becomes each reception frequency from the base unit's perspective.
2+...+ fh-m can be scanned and monitored to enable only the first answering handset, and similar frequency monitoring can be performed when a call is suddenly placed from one handset. Then, subsequent calls from other handsets are disabled.

[Problems to be Solved by the Invention] Adoption of the above-mentioned MCA method requires scanning circuits for at least all channels, resulting in considerable expense. Another drawback is that it takes a long time to connect due to the scanning time, and these drawbacks are exacerbated especially in systems that require a dedicated control channel.

If this could support more handsets with a smaller number of channels, it would be extremely useful for cordless telephone systems, especially those that use weak radio waves as mentioned above, which should be supplied relatively inexpensively. This results in the desired result.

The present invention was made precisely from this motive,
Similar to the parent-child telephone system of traditional wired telephones, even in cordless telephone systems, when trying to connect multiple handsets to a single base unit, for example, a set of transmitting and receiving frequency pairs (device The purpose of the present invention is to provide a communication control method that satisfies sufficient confidentiality or a "priority priority" mode even with Uplex (Bear), and a cordless telephone device for use in this method.

[Means for Solving the Problems] In order to achieve the above object, the present invention first uses a system of one base unit and a plurality of handsets, basically using a pair of transmitting and receiving frequencies (single channel). Only used. That is, the carrier frequency fh transmitted by multiple handsets is all the same single frequency (first frequency), and the carrier frequency fh transmitted by the base unit
b is also a single second frequency, and these first,
Configuring a single channel bear on the second frequency.

However, it goes without saying that this is not the only way to do this.
In the set, there is monitoring whether or not the same frequency fh as the carrier frequency fh emitted by the set actually exists in the antenna;
Provide a detection function.

Then, as a result of the check, if the transmission frequency fh has already been output to the antenna before the transmission itself attempts to start transmission, the transmission is not permitted.

If these are summarized as a summary structure, they are as described in the claims at the beginning of this document.

[Function] According to the configuration of the present invention, each handset has a function of monitoring the carrier frequency fh (the first frequency referred to in the summary) that is emitted by itself, and therefore all handsets emit, If this currently exists on the antenna, even if the user issues a transmission request by operating a response switch or dialing a telephone number (button operation), the frequency fh will actually be used as a carrier. transmission is prohibited.

Therefore, both the response operation on the handset side when hearing the bell tone, and the dialing operation from the handset side are valid only for the handset that performs these operations first. The hand that was operated
Even if there is a set, it is effectively nullified.

To be more specific, as long as the above-mentioned check system is adopted in each handset, for example, when a ring tone is received from a telephone line, the base unit will detect the carrier frequency fb (in the summary) based on this. second frequency)
When the corresponding bell sound signal is transmitted using a telephone receiver, each handset receives the signal with its own built-in receiving circuit, and audibly displays this bell sound simultaneously on the handset or a dedicated speaker or sounding device. However, as a result, when only the handset whose response switch is operated first checks the transmission frequency fh it is trying to emit, it is in a state where this transmission frequency fh is not in use, so-called "channel free". The first handset to respond responds as expected to the base unit using the predetermined frequency fh as the transmitting carrier, but the response is delayed. From the point of view of the handset that operated the switch, the transmission frequency fh that it was trying to transmit is already in use, and the channel is in a so-called "busy" state, so it cannot transmit. It will not be permitted.

The same applies to calls made from the handset side. Starting with the transmission frequency fh being free, only the first handset to place a call will be enabled; subsequent attempts by other handsets to place a call will be prohibited.

Preferably, when the above-mentioned transmission prohibited state occurs, a message is sent to the user via the handset, a dedicated speaker, or a dedicated sounding device, in order to inform the user that the transmission is currently prohibited. To generate a busy sound,
It is preferable to operate an appropriate busy notification means, such as driving an appropriate visual display means to visually display the busy state.

[Embodiment] FIG. 1 shows a preferred embodiment of the communication control method for a cordless telephone system according to the present invention in the form of a flow chart relating to operations within a handset, and FIG. A corresponding circuit portion of a cordless telephone device to which the method of the present invention is applied is schematically shown.

For convenience of understanding, the static configuration shown in the second diagram will be explained.
The base unit BU itself connected to the telephone line may be the same as the conventional one, or it may utilize a frequency check function on the handset H5 side of the present invention, which will be described later, or As already filed for a patent on December 25, 2017, the transmission system that constitutes a transmitting and receiving frequency pair is based on a channel check system that can be applied not only to cordless telephone systems but also to numerical full-duplex communication systems. , and may have a check function for each frequency of reception. In the cordless telephone system of the present invention, it is important that the handset H5 has at least a function to check its own transmission frequency fh, rather than a problem on the base unit BU side. is necessary.

However, in the illustrated case, a plurality of m (≧2) handsets H5 having the same configuration are provided. Therefore, its internal configuration is that one handset H5-
1, other handsets HS are shown only.
-, ~H5-Y are simply shown with rectangular frames. however,
In explanations that are common to all handset IIs, the suffixes "-1" to "-1" to indicate a particular handset IIs will be omitted and the symbol "
Only H5'' is used as a representative.

Further, in the embodiment shown in the second figure, both the base unit BU and the handset H5 adopt a so-called duplexer configuration (details not shown) in the front end portion, and use a single antenna IO. It is assumed that the transmitting and receiving frequencies can be separated and combined, which is the case with most recent cordless telephone devices of this type, but it is of course possible to use a device having two antennas for transmitting and receiving only.

For convenience of explanation, it is assumed here that the transmission carrier frequency fh of each hand set H5 is all 48 MHz, and the transmission carrier frequency f of the base unit BU is 45 MHz, just as an example.

When an incoming call is received from a telephone line (not shown), a bell signal must first be sent to the handset H5 side, but this becomes a transmission request within this base unit BU, and based on this, preferably In accordance with the method for which the applicant has previously applied for a patent, the base unit Bt also checks whether the transmission frequency fb it emits and the reception frequency fh it receives already exist. If both are not present, the bell sound information is placed on the transmission frequency fb and radiated to the antenna from the antenna 10 by frequency modulation or other suitable modulation method.

The frequency fb carrying this bell sound information is used for all hands.
The signals are commonly captured and demodulated by the receiving circuits 13 of the sets H1 to H5-, and audibly displayed on the receiver 14 through a suitable sounding device such as a dual-purpose or dedicated speaker. In other words, for all handsets Hs-+ ~us,
It is set to be able to receive the frequency fb-45 MHz in a steady state.

From this state, referring also to the preferred flowchart shown in the first figure, when the above-mentioned bell tone is heard, one of the handsets H5-, ~H5,
11 (i=1.2., , , , m), when someone operates a response switch (not shown) to answer the call, the handset where the response operation was performed ll5-
, the control circuit 11 attaches the monitoring frequency switching signal Cs to one of the binary logic signals indicating that the transmission carrier frequency fh-48MHz issued by itself should be received, and in response, the receiving circuit 13 It becomes possible to receive a frequency of 48 MHz.

The receiving circuit 13 thereby detects the presence or absence of a 48 MHz signal input to the antenna 10, and outputs a transmission carrier presence/absence signal Dx that selectively indicates the presence or absence of the carrier, also using one of the binary logic signals.

Note that the circuit itself for outputting different logical values depending on the presence or absence of a carrier can be extremely easily obtained by those skilled in the art by appropriately utilizing known and existing electronic circuit technology and logic circuit technology. As described above, even though the transmission carrier frequency fh-48MH2 is detected, the carrier frequency is actually the center frequency, and bands of a predetermined width are provided on both sides of the center frequency. In other words, it is practical and desirable to be configured to detect frequencies that are close enough to cause interference with each other, even if they are not exactly the same frequency.

However, the response operation in the handset H5-, does not affect any other handsets H1, ~H5-i-1:H.
l. , ~H5-, in other words, if the receiving circuit 13 does not detect a frequency that is the same as or in the vicinity of the transmission carrier fh emitted by itself, the control circuit 11 determines that the transmission channel is "vacant" and issues a transmission permission signal S.

As a result, the transmitting circuit 12 places the response signal on the corresponding transmitting carrier frequency fh=48M and performs frequency modulation, etc.
It is transmitted from the antenna 10 using an appropriate modulation method, and thereafter, the base unit BU side receives it and enters a line connection using existing circuits and operations, and at the same time, the hand
On the set H5-me side, the monitoring frequency switching signal C8 is returned to its original logical value, and the receiving circuit 13 receives the predetermined receiving frequency f, -45 sent from the base unit BU.
When M1lz is in a receivable state, full-duplex communication becomes possible.

However, as mentioned above, with the transmission permission, in the state where there is a hand set H5 which is already emitting the transmission carrier frequency fh-48M)I2, some other handset H1, (x#i) When a similar response operation is performed in the handset II S-, the situation is different in this handset II S-.

The control circuit 11 in this handset H5- should also receive the monitoring frequency switching signal C8 at the transmission carrier frequency fh-48MH, which it emits, when its own response switch is operated. In response to this, the receiving circuit 13 becomes ready to receive the center frequency of 48 MHz, but the antenna has already received the frequency fh-48 MH2 emitted by the handset H5-. exists, the transmitting carrier presence/absence signal Dx in the handset H1 emits a logic value signal indicating the presence of the transmitting carrier.

Therefore, the control circuit it, which is fed back this transmission carrier presence/absence signal Dx, determines that the transmission channel is in use and changes the transmission permission signal Sx to a non-significant logical value, that is, a logical value meaning "transmission not permitted." and keep the transmitting circuit 12 inactive.

In the present applicant's practical experiment example, this purpose is achieved by continuing the state in which the power supply to the transmitting circuit 12 is cut off.

In other words, as seen in the above-mentioned handset ll5-, when the transmitting operation of the transmitting circuit 12 is permitted,
The transmission permission signal Sx functions as a signal to close the circuit that supplies power to the transmission circuit 12, and the stiffness is actually
Various configurations can be made using this type of electronic circuit technology as a trigger signal (or base signal) for a suitable switching means such as a transistor.

However, of course, the present invention is not limited to such selective turning on and off of the power source, and for example, a circuit that selectively opens and closes the transmitting circuit output line may be constructed.

In any case, as mentioned above, if a response operation has already been performed on any handset H5-1,
Even if a transmission request based on the bell signal response operation is issued later in another handset H5-, as described above, the transmission circuit 12 does not operate effectively and the transmission request is sent via the reception circuit 13. As long as the monitoring state of the transmitting carrier by the control circuit 11 is maintained and the response switch of the handset Is-, which is not permitted to transmit, is turned off,
This state will continue.

In this case, when the transmitting carrier frequency is determined to be busy on the handset H5 side,
It is desirable that the system be configured to emit an appropriate audible busy tone immediately or after a predetermined period of time has elapsed from the time of the determination, via a busy tone notification means using an appropriate sounding device such as the telephone receiver 14. In addition, it may be possible to automatically go off-hook (returning the response switch) after a predetermined period of time has elapsed, but considering the ease of use of this type of device, there is generally no need to go that far. (This doesn't mean you can't do it). If you hear a busy sound,
This is because the user will know that there was a handset H5 that answered earlier, and will naturally return the answer switch.

The embodiments shown in Figures 1 and 2 will be described in this way, but of course, this operation is performed under the condition that any handset H5- is making a call somewhere and the call has already been made. (on other hand sets)! 5-x(x#t)
This also applies when someone attempts to make a call. This is because if the calling operation is a transmission request, when similarly checking the transmission carrier frequency fh emitted by itself with the transmission request, it can be found that the frequency fh is already present in the antenna.

A preferred embodiment of the present invention has been described above, but some supplementary information will be added below for reference.The control circuit 11 has micro- Using a computer is the most common and convenient method.

In addition, the monitoring frequency switching signal Cs issued by the control circuit 11
Although the present invention does not specifically define the procedure for changing the center frequency monitored by the receiving circuit 13 depending on the logic level of It is easiest, rational, and economical to make it variable.

For example, it would be possible to provide a receiving section dedicated to each center frequency of 45 MHz and 48 MHz in the receiving circuit 13, and configure the monitoring frequency switching signal Cs to select one of the receiving sections. The circuit scale becomes too large, which may become a factor that hinders the miniaturization and cost reduction of devices. Therefore, in order to standardize circuit components or circuit structures that can be used in common by changing the reception frequency as much as possible, it is most desirable to make the band pass filter characteristics variable as described above, and moreover, to be able to directly control the changes using electrical signals. .

Incidentally, in an experimental example in which the present applicant applied the method of the embodiment shown in Figures 1 and 2 to a cordless telephone system,
The time required for the receiving circuit system to stabilize from the start of each channel check until it is suitable for judgment is about 50m5ec, and by the time it stabilizes, the channel state has already been judged by the control circuit 11, so the judgment time is It is almost zero, which means that the stabilization time and the judgment time can be considered to be almost equal.

[Effects] As is clear from the above explanation, according to the present invention,
When attempting to expand the number of handsets H5 to one base unit BU in a cordless telephone system, the following effects can be obtained.

■ There is no need to simply increase the number of channels used depending on the number of handsets, and a single transmit/receive frequency pair (single Even if only one channel is used, it is possible to satisfy the necessary secret function or "priority priority" mode.

■As a result, a type of simple exchange was provided at an extremely low cost.

■ Also, adding more handsets is extremely easy and free. In principle, there is no upper limit to the number of devices that can be used. M
In the case of a conventional example that employs the CA system, there is a practical limit to the number of channels that can be taken within the allowed band, and therefore there is also a practical upper limit to the number of handsets that can be used.

■ In this type of cordless telephone system, various control information such as speed dial information can also be exchanged between the base unit and the handset. Since only the hardware and software used for these controls, such as dials and memory, are used for all hand
Set H5 may be used in common, and in that sense, an extremely rational system can be constructed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating a preferred embodiment of a communication control method for a cordless telephone system according to the present invention in accordance with a flow chart, and FIG. 2 is an embodiment of a cordless telephone device applicable to the present invention. FIG. 3 is an explanatory diagram of the basic conceptual structure of this type of cordless telephone system. In the figure, IO is an antenna, 11 is a control circuit, 12 is a transmitting circuit, 13 is a receiving circuit, Dx is a transmission carrier presence/absence signal, and C
s is the monitoring frequency switching signal, Sx is the transmission permission signal, BU
is a base unit, and HS and HS-1 to H5° are handsets. Applicant Unison Co., Ltd. L Ox Transmission carrier presence/absence signal Negative Monitoring frequency switching signal Sx Transmission permission signal f, Transmission carrier f1 from base unit BU
Hand set l-1s-, its transmitting carrier f (-1$8MN,) Figure 2f. , your work ~ "1, ten [

Claims (3)

[Claims] (1) In a cordless telephone system that includes a base unit that is wired to a telephone line and a handset that can be coupled to the base unit by radio frequency, multiple handsets may be connected to one base unit. A communication control method when the plurality of handsets transmit data to the base unit, the transmitting carrier frequency being all the same first frequency, and the base unit transmitting to the base unit. The transmission carrier frequency used when transmitting to each of the handsets is also a second frequency, which is different from the first frequency, but is still single; Upon request, before transmitting the information to be transmitted on the carrier of the first frequency, it is detected whether the first frequency already exists in the antenna; A communication control method in a cordless telephone system, characterized in that: disallowing the transmission if the first frequency does not exist, and permitting the transmission only if the first frequency does not exist. (2) A cordless telephone device comprising a plurality of handsets and a base unit; each of the plurality of handsets has a transmitting circuit using the same first frequency as a carrier; , the base unit has a receiving circuit that uses a second frequency as a carrier, which is different from the first frequency but is also single; the base unit has a transmitting circuit that uses the second frequency as a transmission carrier; and a receiving circuit as a receiving carrier; and each of the handsets further includes, when a transmission request to the base unit is issued, the receiving circuit in the handset transmits the first frequency. When the receiving circuit receives the first frequency, it disallows transmission using the first frequency as a carrier accompanying the transmission request, and only when the first frequency is not received. A cordless telephone device comprising: a control circuit that permits transmission using the first frequency as a carrier from the transmitting circuit in the handset based on the transmission request. (3) The control circuit enables the reception circuit in the handset to receive signals using the second frequency as a carrier in a steady state, and after permitting transmission based on the transmission request, receives the signal on the first frequency. 3. The cordless telephone device according to claim 2, further comprising: switching from the enabled state to the receivable state of a signal using the second frequency as a carrier.