JPH02184149A - cordless telephone device - Google Patents

Abstract

PURPOSE:To return a mobile equipment in a speech zone by attenuating or stopping the radiation of a radio wave once when a fixed station discriminates the mobile equipment to be at the outside of the speech zone and activating a circuit identifying the electric field strength of the mobile equipment forcedly, thereby informing the presence of outside of the speech zone to the user. CONSTITUTION:When an arrived radio wave from a mobile equipment 2 inputted from the reception antenna 12 of a stationary station 1 to a radio reception circuit 10 reaches the setting level of an electric field strength identification circuit 11 or below, a control circuit 7 interrupts a switching circuit 14, interrupts the power supply of a transmission circuit 18 to bring the state into the stop state, the radiation of a radio wave is stopped and a call circuit 5 keeps the speech state. Since the radio wave from the stationary station 1 is interrupted in the mobile equipment 2, a carrier detection circuit 23 identifying the electric field strength outputs a signal being outside of the speech zone to the control circuit 16 and the control circuit 16 activates a buzzer 26 and an LED 27 to apply visual and audible announcement to the user for the presence at the outside of the speech zone. Thus, the return into the speech zone is urged and the interruption of the speech is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial field of application to which the invention pertains The present invention relates to a cordless telephone device.

(2) Conventional technology and its problems Conventional cordless telephone equipment equipped with a circuit for identifying electric field strength uses a circuit to identify electric field strength to maintain a certain level of call quality during telephone calls over the central office line. The field strength of radio waves is monitored, and if the field strength falls below a set level, the mobile device displays an indication that the call is out of range, but the fixed station processes the call to be disconnected. However, because the field strength of the radio waves arriving at the mobile device and the field strength of the radio waves arriving at the fixed station do not necessarily match, if the fixed station determines that the call is out of range before the mobile device does, the mobile device cannot use the The drawback was that the fixed station opened the line without indicating to the person that the call was out of range.

(3) Purpose of the Invention The purpose of the present invention is to solve these drawbacks, and to make it possible for the mobile device to recognize that it is out of communication range even if the fixed station determines that it is out of communication range before the mobile device does. A cordless telephone device is provided.

(4) Structure and operation of the invention To achieve this object, the cordless telephone device of the present invention attenuates or attenuates the emission of radio waves from the fixed station once the fixed station determines that the mobile device is out of communication range. It has a configuration characterized in that the mobile device stops and forcibly operates a circuit that identifies the electric field strength of the mobile device to notify the user that the mobile device is out of the communication range, and prompts the mobile device to return to the communication range.

The present invention will be explained in detail below using the drawings.

The figure shows an embodiment of the present invention, where ■ is a fixed station and 2 is a mobile device. In the fixed station 1, 3 is a telephone line, 4 is an incoming signal detection circuit, 5 is a communication circuit, 6 is a selection signal sending circuit, 7 is a control circuit, 8 is a radio transmitting circuit, 9 is a transmitting antenna, and 10 is a radio receiving circuit. , 11 is a carrier detection circuit used as a circuit for identifying electric field strength in the radio receiving circuit, 12 is a receiving antenna, 13 is a frequency synthesizer, and 14 turns on/off the power of the radio transmitting circuit 8 according to the signal from the control circuit 7. 15 is a power supply circuit.

In the mobile device 2, 16 is a control circuit, 17 is a keyboard switch, 18 is a transmitter, 19 is a radio transmitting circuit, 20 is a transmitting antenna, 21 is a receiver, 22 is a radio receiving circuit, 2
3 is a carrier detection circuit used as a circuit for identifying the electric field strength within the radio receiving circuit 22; 24 is a receiving antenna;
25 is a frequency synthesizer, 26 is a buzzer that audibly indicates to the user that the communication area is out of range, 27 is an LED that visually indicates to the user that the communication area is out of range, and 28 is a battery that supplies current to each circuit of the mobile device.

The incoming calls from the telephone line 3, the outgoing calls from the mobile device 2, and the central office line calls from the mobile device 2 are the same as those of a normal cordless telephone device, and will therefore be omitted.

The operation when the mobile device 2 moves from within the communication range to outside the communication range during a telephone call will be explained.

First, when mobile@2 is within the calling range, fixed station 1
The incoming radio wave from the mobile device 2 is inputted from the receiving antenna 12 to the wireless receiving circuit 10 by the circuit 1 which identifies the electric field strength.
1, the electric field strength identifying circuit 11 outputs a signal to the control circuit 7 indicating that the mobile device 2 is within the communication range. Even in movement a2, the incoming radio wave from the fixed station l that is input from the reception antenna 24 to the radio reception circuit 22 is higher than the set level of the field strength identification circuit 23, so the field strength identification circuit 23 moves. The device 2 outputs a signal indicating that it is within the communication range to the control circuit 16. In the above case, the call continues without any problem.

Next, the operation when the mobile device 2 itself detects before the fixed station l that the mobile device 2 has moved from within the communication range to outside the communication range will be described.

The incoming radio waves from the fixed station 1 that are input from the reception antenna 24 of the mobile device 2 to the radio reception circuit 22 are below the set level of the field strength identification circuit 23, and the field strength identification circuit 23 receives a signal indicating that the communication area is out of range. is output to the control circuit 16. a control circuit 16 that continuously detects the signal for a certain period of time;
drives the buzzer 26 and LED 27 to provide an audible and visible display to the user that the user is out of the calling area, thereby prompting the user to return to the calling area. This operation is the same as that of a conventional cordless telephone device, and if the mobile device 2 returns to the calling range within a certain period of time after the above display, the call is continued, and if it does not return, the mobile device performs a process of disconnecting the call.

Next, an explanation will be given of the operation when the fixed station 1 detects that the mobile device 2 has moved from within the communication range to outside the communication range before the mobile device 2 does.

The incoming radio wave from the mobile 12 that is manually input from the receiving antenna 12 of the fixed station 1 to the radio receiving circuit 10 is at the set level of the circuit 11 that identifies the field strength (for example, input field strength is 2μ).
The circuit 11 for identifying electric field strength outputs a signal indicating that the communication area is out of range to the control circuit 7. The control circuit 7 that has continuously detected the signal for a certain period of time (for example, 10 seconds) turns off the switch circuit 14, turns off the power to the transmitter circuit 8, and stops transmitting, and stops emitting radio waves, but the call circuit 5 does not continue to make calls. maintain the condition. At this time, in the mobile device 2, the radio waves from the fixed station 1 have been cut off, so the carrier detection circuit 23 that identifies the field strength outputs a signal indicating that the mobile device 2 is out of communication range to the control circuit 16. The control circuit 16 that detected this signal is the buzzer 26
Then, the LED 27 is driven to provide an audible and visible display to the user that the user is out of the calling area, thereby prompting the user to return to the calling area. Here, if mobile device 2 returns to the calling range,
Since the incoming radio wave from the mobile device 2 inputted from the receiving antenna 12 of the fixed station to the radio receiving circuit 10 is higher than the setting level of the circuit 11 for identifying electric field strength, the circuit 11 for identifying electric field strength is within the communication range. The signal is output to the control circuit 7, the control circuit 7 is connected to the switch circuit 14, and the transmission circuit 8 is connected to the control circuit 7.
By supplying power to the device, calls can be made again.

On the other hand, if the mobile device 2 does not return to the calling range even after a certain period of time (for example, 20 seconds) has elapsed after the fixed station 1 stopped emitting radio waves, the call is disconnected.

The above explanation describes the case where radio wave emission is stopped, but
In order to attenuate the emission of radio waves, an attenuation circuit may be inserted between the radio transmission circuit 8 of the fixed station 1 and the transmission antenna 9, and the amount of attenuation may be changed by the control circuit 7.

(5) As described in detail, according to the present invention, when the fixed station detects that the mobile device is out of communication range before the mobile device, the mobile device can attenuate or stop the emission of radio waves from the fixed station. The device can display an out-of-call area display to easily prompt the user to return to the calling area, which has the effect of avoiding call disconnections.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of the present invention. ■...Fixed station, 2...Mobile device, 3...Telephone line, 4...Incoming signal detection circuit, 5...Telephone circuit,
6... Selection signal sending circuit, 7.16... Control circuit, 8.19... Radio transmitting circuit, 9.20... Transmitting antenna, 10.22... Radio receiving circuit, 112
3...Circuit for identifying electric field strength, 12.24...
・Receiving antenna, 13. 25... Frequency synthesizer, 14... Switch circuit, 15... Power supply circuit, 17... Keyboard switch, 18... Transmitter, 21... Receiver, 26.・Buzzer 27
...LED, 28...battery. Thousand Sieve Tit Book (C) May 11, 1999

Claims (1)

[Claims] In a cordless telephone device in which a mobile device and a fixed station are equipped with a circuit for identifying the electric field strength of the other party, when the mobile device is talking to a telephone line through a wireless line, the electric field strength arriving at the fixed station is higher than the electric field strength. When the level falls below the setting level of the identifying circuit, the radio wave emission of the fixed station is attenuated or stopped, the mobile equipment's circuit that identifies the electric field strength is operated, and it is displayed that it is out of the communication range. A cordless telephone device comprising: