EP0268902B2 - Coded remote control with a code-changing facility - Google Patents

Description

The present invention relates to a coded remote control with a transmitter for sending a coded message and a receiver for receiving the coded message, in which the received message in a first comparison device with a changeable code stored in a writable memory and in a second comparison stage with an unchangeable code Fixed code is compared, on the one hand another device emits a control signal if the received message matches the changeable code and, on the other hand, if the received message matches the fixed code, a write lock for the writable memory is released in order to rewrite this memory with a changed code to enable.

Such remote controls are used in particular in the automotive industry to control the locking / unlocking of doors, an alarm, to control vehicle blocking elements, etc.

Usually, the transmitter and receiver are combined with the same fixed code, which causes numerous difficulties in tape assembly, in which the transmitter and receiver are separate. In addition, the arrangement of a new transmitter if the old one is lost, destroyed, or a new transmitter is required brings with it the need for expensive installation and difficult intervention.

In order to remedy this difficulty, it has been proposed to equip the remote control with programming devices, for example with a switch which can be operated by the user and which enables the programming of a new coded message which can be stored (eg FR-A-2 494 534).

Such an arrangement has the considerable disadvantage that the stored code can be changed over by an unauthorized third party who has a new transmitter and has access to the programming devices. Even if the programming devices can only be effective when the already stored message is sent, as a variant of the proposed device provides, there is still the risk of a code changeover by third parties.

A lock which can be actuated by an electronic key is known from US Pat. No. 4,392,133. In this lock, a changeable code is stored in a memory, which is compared to the electronic coding attached to the key. If the two codes match, an enable signal is issued to open the lock. The write lock of the memory, which prevents unauthorized modification of the code, can be released by a second key, which carries an unlock code and puts the memory in a writable state. The changed code can then be transferred to the memory using a key with a changed coding. This key is the only one that can be used to open the lock until the next code change. In the known lock, the code stored in the memory can consequently be changed in a convenient manner.

In the case of a register block which can contain several control codes, e.g. B. the respective codes for different users, a difficulty may arise if a transmitter whose code has been stored is lost. In fact, the code in the memory that has become useless cannot be replaced directly by the code of a new transmitter, since the memory space is unknown. It is therefore not only necessary to re-enter the code of this new transmitter, but also the codes of all other transmitters which are still valid. This process is time consuming and not very flexible.

The object of the present invention is to eliminate these difficulties which occur in the known devices.

This object is achieved in that the writable memory of the receiver consists of a block of registers, one register each storing a code, and that only a further, programmable transmitter can transmit the aforementioned and predetermined fixed code and then a sequential number or Sends out address that corresponds to one of the registers or is assigned, and the programmable transmitter sends out a control code which the receiver stores in the register selected by means of the serial number or address.

The programmable transmitter preferably works with coding wheels or a keyboard.

In one embodiment of the invention, the first comparison stage, after receiving the message sent by the non-programmable transmitter, compares the codes stored in the registers in succession with the received message and the further device emits a control signal if the received message matches one of the changeable codes.

The system according to the invention enables the coding of a receiver after delivery of the vehicle using a transmitter with any code in which the fixed code previously defined for the vehicle is sent using the programmable transmitter. This programmable transmitter, which is only in the possession of authorized repair companies, therefore enables remote entry of a code into the memory which does not contain it or which contains a code other than that of the transmitter.

The process is the same if the memory already contains a code and the user wants to change this code. This is the case, for example, if the transmitter is lost or destroyed. The user can then purchase a new transmitter with any code that can be entered into the memory of the receiver instead of the old code, provided a programmable memory and the predetermined fixed code of the vehicle are available. This fixed code thus represents a memory access code.

In the case of a register block which can contain several control codes, e.g. B. the respective codes for different users, the process is the same. By entering a new code, the code contained in the last register is output from the memory.

The programmable transmitter is a simple and inexpensive device, which the dealers can use easily and economically.

The systematic shift described above can be difficult if a transmitter whose code has been stored is lost. In fact, the code in the memory that has become useless cannot be replaced directly by the code of a new transmitter, since the memory space is unknown. It is therefore not only necessary to re-enter the code of this new transmitter, but also the codes of all other transmitters which are still valid. This process is time consuming and not very flexible.

The invention makes it possible to solve this problem. For this purpose, after the programmable transmitter has sent the aforementioned and previously defined fixed code, said programmable transmitter sends out a sequential number which corresponds to one of the registers, and the receiver stores the control code in the memory compartment to which this sequential number is assigned.

This sequential number is therefore assigned to the sender. With this transmitter, it is sufficient to save the code of the replacement transmitter, specifying the same serial number as the number that was lost or destroyed. The serial number can be entered on the transmitter in the form of a number or, preferably, in the form of a color. In this case, the programmable transmitter has sequential buttons with different colors. After storing the code, each transmitter receives a marking with the color of the button used in the form of an indelible paint, a colored label or a pen made of colored plastic, which is inserted into an opening of the receiver.

Claims (2)

1. Coded remote control comprising an emitter for emitting a coded information message and a receiver for receiving the coded information message, in which the received message is compared in a first comparison device with a modifiable code, stored in a memory which can be written in, and in a second comparison stage with an unchangeable fixed code, and, on the one hand, an additional device emits a control signal when the received message matches the modifiable code and, on the other hand, when the received message matches the fixed code a barrier to writing in the memory which can be written in is removed, to make possible renewed writing in this memory of a modified code, characterized in that the memory of the receiver which can be written in consists of a block of registers, where each register stores one code, and that only one other programmable emitter can emit the said previously established fixed code and then emits a sequence number or address which corresponds to or is associated with one of the registers, and the programmable emitter emits a control code which the receiver, by means of the sequence number or address, stores in the selected register.
2. Coded remote control according to claim 1, characterized in that the first comparison stage after reception of the information message emitted by the emitter compares the codes stored in the registers successively with the information massage received and the additional device produces a control signal when the information message received matches one of the modifiable codes.