JP3192870B2 - Cordless telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone comprising a master unit connected to a general subscriber's telephone network and a plurality of slave units connected to the master unit via a wireless line. .

[0002]

2. Description of the Related Art For a cordless telephone in the United States, the transmission frequency bands for both the base unit and the handset are defined by the FCC standard (Part 15). That is, the transmission frequency band of the master unit is 46.60 MHZ to 46.98 MHZ, the transmission frequency band of the slave unit is 49.66 MHZ to 50.00 MHZ,
It has been established.

The number of channels is determined to be ten, and the frequency of each channel is as shown in the table of FIG.

For this reason, the cordless telephone is provided with a receiving circuit unit for receiving the transmission frequency band of the slave unit in the master unit,
One slave circuit unit is provided for each slave unit to receive the transmission frequency band of the master unit. The same applies to a cordless telephone having a plurality of cordless handsets.

[0005]

However, in order for two of the plurality of slave units (slave unit 1 and slave unit 2) to communicate with each other (inter-slave unit call), a conventional parent device is required. The relay of the machine was necessary.

That is, the transmission signal from the slave unit 1 and the transmission signal from the slave unit 2 in the same frequency band and different channels are received by separate receiving circuit units on the master unit side, and are further separated by separate transmitting circuit units. The transmission signal of the slave 1 must be transmitted to the slave 2, and the transmission signal of the slave 2 has to be transmitted to the slave 1 using the channel No.

In this case, two receiving circuit units and two
Since two transmission circuits are required, it is disadvantageous in terms of cost and space.

[0008]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to realize a communication between slave units without relaying a master unit and without violating standards such as FCC. In a cordless telephone comprising a master unit connected to a general subscriber's telephone network and a plurality of slave units connected to the master unit via a wireless line, the reception circuit unit of each slave unit includes: A reception frequency band switching unit that switches between receiving a signal in the transmission frequency band of the master unit and a signal in the transmission frequency band of the slave unit is provided, and a control device unit provided in each slave unit includes another slave unit. When talking with the handset, the transmission circuit unit transmits a signal on a predetermined channel of the transmission frequency band of the slave unit, and the reception circuit unit transmits a signal on the transmission frequency band of the slave unit and on a channel different from the predetermined channel at the time of the transmission. Control to receive .

[0009]

According to the above arrangement, it is possible to perform a call between slave units without relaying by the master unit and without violating standards such as FCC.

For example, the handset 1 transmits a signal on the transmission frequency band channel 1 of the handset and receives a signal on the transmission frequency band channel 2 of the handset. On the other hand, handset 2
Transmits a signal on the transmission frequency band channel 2 of the handset and receives a signal on the transmission frequency band channel 1 of the handset. Thus, between the child device 1 and the child device 2,
Calls between handset units become possible.

[0011]

FIG. 1 is a system block diagram of a cordless telephone according to the present invention comprising a master unit and a plurality of slave units.

In FIG. 1, 1 is a general subscriber telephone network,
Reference numeral 2 denotes a wired communication line, and a base unit 3 of the cordless telephone is connected to the general subscriber's telephone network 1 via the wired communication line 2. Reference numerals 4 and 5 denote a first slave unit and a second slave unit connected to the master unit 3 via the wireless line 19.

FIG. 2 is a block diagram showing the inside of the master unit 3.

The base unit 3 includes a control unit for controlling the whole base unit, for example, a control unit 6 composed of a microcomputer, a telephone unit 7 having a telephone function such as a ringer circuit, and a first slave unit 4.
And a transmission circuit unit 8 for transmitting a signal to the second slave unit 5
A receiving circuit unit 9 for receiving signals in a transmission frequency band from the first slave unit 4 and the second slave unit 5, an antenna 10,
And an inter-slave communication button 11.

FIG. 3 is a block diagram showing the inside of the first handset 4 and the second handset 5. Each of the slave units 4 and 5 includes a control unit for controlling the entire slave unit, for example, a control unit 12 including a microcomputer, a transmission circuit unit 13 for transmitting a signal to the master unit 3, A reception circuit unit 14 for receiving a signal in the transmission frequency band, a reception frequency band switching unit 15 for switching to reception of the transmission frequency band of the child device in order to receive a signal from another child device, an antenna 16, Device (microphone and speaker) 17 and rechargeable battery 18
And

Next, the operation of the cordless telephone according to the present invention will be described.

First, when a normal base unit 3 communicates with a slave unit on channel 1 in the chart of FIG. 4, the transmission circuit unit 8 of the base unit 3 transmits a signal using a carrier wave of 46.610 MHz.
The transmission circuit unit 13 of the slave unit 4 or 5 transmits a signal using a carrier wave of 49.670 MHZ. Receiving circuit section 9 of base unit 3 receives a signal of a carrier wave of 49.670 MHZ from slave unit 4 or 5, and receiving circuit unit 14 of slave unit 4 or 5 receives a signal from base unit 3.
6. A signal of a carrier of 610 MHZ is received.

Next, the first slave unit 4 is relayed without relay of the master unit 3.
And the operation in the case of making a call between the child devices with the second child device 5 will be described.

When the talk button 11 between the slave units of the master unit 3 is pressed,
The information that the communication between the slaves is performed and the information that the transmission signal of the first slave 4 uses the channel 1 and the transmission signal of the second slave 5 uses the channel 2 are controlled by the master 3. The signal is output from the device unit 6 and transmitted to the first slave unit 4 and the second slave unit 5 via the transmission circuit unit 8.

Upon receiving this information, the control unit 12 of the first slave unit 4 sends a 49.670 MHZ signal from the transmission circuit unit 13.
The transmission signal is transmitted on the carrier of (Channel 1). or,
By controlling the reception frequency band switching unit 15, the reception circuit unit 14 is switched from the state of receiving the signal of the transmission frequency band of the master unit to the state of receiving the signal of the transmission frequency band of the slave unit, and the 49.845 MHZ (channel 2) ) Is set to a state of receiving the carrier transmission signal (the transmission signal of the second slave unit 5).

Similarly, the control unit 12 of the second slave unit 5 that has received the information from the master unit 3 transmits a transmission signal from the transmission circuit unit 13 using a carrier of 49.845 MHZ (channel 2). Also, by controlling the reception frequency band switching unit 15, the reception circuit unit 14 is switched from the state of receiving the transmission frequency band of the master unit to the state of receiving the transmission frequency band of the slave unit, and the 49.670 MHZ (channel 1) It is set to a state of receiving a carrier transmission signal (the transmission signal of the first slave unit 5).

As described above, the first slave unit 4 and the second slave unit
Communication between the child devices with the child device 5 is possible.

[0023]

According to the present invention, it is possible to perform a call between slave units without relaying the master unit and without violating the standards such as FCC. Therefore, it is advantageous in terms of cost and space as compared with the conventional case of communication between slave units, which requires two receivers and two transmitters in the master unit.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing the entire cordless telephone of the present invention.

FIG. 2 is a block diagram showing a base unit of the cordless telephone according to the present invention.

FIG. 3 is a block diagram showing a slave unit of the cordless telephone according to the present invention.

FIG. 4 is a table showing a relationship between each channel and a transmission frequency of a parent device and a transmission frequency of a child device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 General subscriber telephone network 3 Base unit 4 1st sub unit 5 2nd sub unit 12 Control unit 13 Transmission unit of sub unit 14 Receiving circuit unit of sub unit 15 Reception frequency band switching unit 19 Wireless line

Claims (1)

(57) [Claims] 1. A cordless telephone comprising a master unit connected to a general subscriber's telephone network and a plurality of slave units connected to the master unit via a wireless line. A reception frequency band switching unit that switches between receiving a signal in the transmission frequency band of the master unit and a signal in the transmission frequency band of the slave unit is provided, and a control unit provided in each slave unit includes: When talking with another slave unit, the transmission circuit unit transmits a signal on a predetermined channel in the transmission frequency band of the slave unit, and the reception circuit unit is in the transmission frequency band of the slave unit and is different from the predetermined channel at the time of the transmission. A cordless telephone characterized by controlling to receive a signal on a channel.