JPS61214629A - Communication system for cordless telephone - Google Patents

Abstract

PURPOSE:To connect many portable units with one set of base unit by executing a decision by the base unit, and receiving a dialing pulse or an MF tone from the portable unit only at the time of the security code concerned. CONSTITUTION:The portable unit 10 turns on a talk switch 19 in case of dialing. By the control of a CPU 17, the FFH of 20 bytes is transmitted automatically as a synchronous code from a transmitting circuit 16. The portable unit 10 sidfe transmits a private code successively three times by following the synchronous code. The private code of a try 3 is awaited, and only in case when it is received correctly two times or above among three times of the tries 1-3, it is decided to be the correct private code concerned, and a transmitting circuit 6 is operated. The portable unit 10 transmits a dialing signal by inputting a key, and the communication can be possible. In such a way, with respect to one set of base unit, many portable units can be combined and used.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a telephone call system for a cordless telephone.

BACKGROUND OF THE INVENTION In recent years, there has been active development of improvements and multi-functionality for telephones. Some of these are cordless so that you are not limited to where you can talk. In this system, a base unit is in charge of connection to a telephone line, and a portable unit is attached to the base unit so that it is possible to communicate with the outside via the base unit. Conventionally, the portable unit transmits a security tone signal to the base unit using FM waves, and the base unit uses a tone detector to determine the received tone. It accepts dialing from the portable unit and allows connection to an external line. Also, during a call, a tone signal is always superimposed on the voice signal from the portable unit and transmitted, and when this tone signal is detected and no longer detected, the base unit disconnects from the external line and stops the call. It is to end it.

Problems to be Solved by the Invention However, when using such a conventional method, there are the following problems. First of all, security must be ensured in this type of telephone, and according to the conventional method, a call is made by a portable unit equipped with the same tone signal on the same channel through another person's base unit. There is a possibility that it will be stored away. This is because even if the device has multiple tone signals, if it has a tone switching function, it can be matched with the tone signal of another person relatively easily, making it possible to make calls as described above. However, it cannot be said that sufficient security functions are ensured. Furthermore, in the case of tone signals, there are only a limited number of types of tones, so it is not possible to use a large number of portable units in combination with one base unit.

Therefore, the present invention can dramatically improve the security ability and prevent troubles such as unauthorized use by another person's portable unit, and also allows a large number of portable units to be connected to one base unit. The purpose of the present invention is to provide a cordless telephone call system that allows for communication.

Means for Solving the Problems The present invention provides a cordless telephone that uses a cordless portable unit 10 for a base unit 1.
Prior to transmitting a dialing pulse or MF tone from the portable unit 10 to the base unit 1, a security code is transmitted, and the base unit 1 that receives this security code determines whether or not the security code is the applicable security code. A system is adopted in which dialing pulses or MF tones from the portable unit 10 are accepted only when the code is a code.

Since the base unit 1 determines the suitability of the portable unit 10 by transmitting and receiving an encoded security code, the security capability can be improved compared to the tone signal method, and unauthorized use by another person's portable unit can be prevented. This means that the occurrence can be prevented.

Embodiment A first embodiment of the present invention will be described based on the drawings. First, Figure 1 shows the base unit 1 and portable unit 10.
The configuration is shown as a block diagram.

The base unit 1 is connected to an external telephone line, and has a connection circuit 3 controlled by the CPU 2 and composed of relays, transistors, etc. A receiving circuit 4 for amplifying and detecting incoming radio waves is connected to this connecting circuit 3 via an audio amplifying circuit 5. Further, a transmission system circuit 6 is connected to the CPU 2. Furthermore, the receiving circuit 4
- A waveform shaping circuit and parallel/serial conversion circuit 7 is interposed between the CPUs 2. As shown in FIG. 2, this waveform shaping circuit & parallel/serial conversion circuit 7 is composed of an FM demodulation circuit 7a, a waveform shaping circuit 7b, and a parallel/serial converter 7c.
The demodulation circuit 7a is a circuit that is originally provided in a cordless telephone and is also used for voice demodulation. On the other hand, the portable unit 10 includes a receiving circuit 11 for amplifying and detecting incoming radio waves, an audio amplifying circuit 12, and a speaker 13, as well as a microphone 14, an audio amplifying circuit 15, and an oscillating circuit.

It has a transmitting circuit 16 having modulation and amplification functions.

Furthermore, a CPU 17 is built in, and the transmitting circuit 16/CPU
A serial/parallel conversion circuit and waveform shaping circuit 18 is interposed between the serial and parallel converters 17. As shown in FIG. 3, this serial-to-parallel conversion circuit & waveform shaping circuit 18 consists of an FM modulation circuit 18a and a parallel/serial converter 18b. The same circuit is used for both purposes. Such a portable unit 10 is equipped with a talk switch 19, and dialing is performed by turning on the talk switch 19.

Therefore, in one embodiment, the C of the portable unit 10 is
Store the security code on the PU17 side, and before dialing this talk switch 19 at 08:00,
This portable unit 10 automatically transmits a security code to the base unit 1. The format for sending and receiving this security code is shown in FIG. This security code consists of a synchronization code (20 bytes of FFH) and a three-time private code (
It consists of a 4-byte code (shown here as ABCD), and the start-stop synchronization method (FSK) is used for transmission and reception. Parity, framing, and overflow error checks are then performed on each byte of data.

The operation of transmitting and receiving the security code at the start of one call will now be described with reference to the flowchart shown in FIG. First, the portable unit 10 turns on the talk switch 19 when dialing. As a result, C.P.
2 as a synchronization code from the transmitting circuit 16 under U17 control.
A FFH of 0 bytes is automatically sent. The base unit 1 receives this synchronization code, but when it detects 10 consecutive bytes of FF, it enters a state of waiting for the first byte of the private code (specifically, data A). Time T indicates this.

On the other hand, on the portable unit 10 side, the private code is sequentially transmitted three times following the synchronization code. This is indicated by Trie 1, Trie 2, and Trie 3.

On the base unit 1 side, when the A data of the private code is detected, it waits for the next B data, and receives the 4-digit private code in the order of A→B4C→D.

At this time, when receiving an error or different data while receiving the private code of try 1, base unit 1 waits for the private code of try 2.

If there is an error in try 2 as well, wait for the private code of try 3. Only if two or more of these three tries 1 to 3 are correctly received, the CP of base unit 1 is determined to be the correct private code.
U2 makes the determination and activates the transmitting circuit 6. That is, the hook switch is turned on (the line DC circuit is turned on) and the portable unit 10 hears the line tone 2 indicating that a call is possible. Therefore, in the portable unit 10, the dialing signal (or MF tone...
- Dual Tone Multi Frequency) is received by the base unit 1, and the base unit 1 sends it out to the telephone line, making it possible to make one phone call.

In this way, only this portable unit 10 can make one outgoing call via this base unit 1.

Next, the transmission and reception of the security code during a call will be explained with reference to the flowchart of FIG. During the call, the portable unit 10 transmits a security code at 5 minute intervals (during which time the call is temporarily interrupted).

On the other hand, the base unit 1 side constantly monitors the arrival of the security code during the call, and if it does not receive the security code after 6 minutes or more, or if it does, the incoming code does not match the security code. In this case, the base unit 1 forcibly disconnects the line, stops transmission to the portable unit 10, and ends one call. In this way, the availability of only the portable unit 10 is maintained during a call.

According to this embodiment, the encoded security code method is adopted to determine the validity of the portable unit 10 with respect to the base unit 1 to enable a call, and furthermore, to monitor during the call. Therefore, the security capability can be dramatically improved compared to the conventional tone signaling method. This makes it possible to prevent troubles such as unauthorized use or interference by someone else's portable unit. Furthermore, by adopting the encoded security code method as in this embodiment, the number of types can be increased, and a large number of portable units 10 can be used in combination with one base unit 1. and can meet various needs.

Effects of the Invention As described above, the present invention uses a security code to determine whether the portable unit is suitable for the base unit before making a call, so compared to the conventional security tone signal method, Security capabilities can be dramatically improved, and troubles such as unauthorized use or interference by other people's portable units can be prevented, and the security code method allows multiple portable units to be connected to one base unit. Furthermore, since the security code is checked regularly even during a call, the security capability can be made more reliable.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram, FIGS. 2 and 3 are partial circuit diagrams, FIG. 4 is a timing chart showing the format of security code transmission and reception, and FIG. Figure 5 is a flowchart when starting a call.
FIG. 6 is a flowchart during a call. 1...Base unit, 10...Portable unit 3"Figure"O"7

Claims (1)

[Claims] 1. In a cordless telephone that uses a cordless portable unit for a base unit, a security code is transmitted prior to transmission of a dialing pulse or MF tone from the portable unit to the base unit, and the security code is transmitted from the portable unit to the base unit. A cordless telephone call method characterized in that the base unit that receives the code determines whether or not the code is the applicable security code, and only when the code is the applicable security code, the dialing pulse or MF tone from the portable unit is accepted. . 2. In a cordless telephone that uses a cordless portable unit for the base unit, the base unit transmits a security code before transmitting a dialing pulse or MF tone from the portable unit to the base unit, and receives the security code. The dialing pulse or MF tone from the portable unit is accepted only when the security code is the applicable security code, and the communication between the portable unit and the base unit is performed during the call after acceptance. A cordless phone call system characterized by transmitting and receiving a security code at fixed time intervals, and terminating the call when the security code cannot be determined.