"Improved peripheral device "

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The invention relates to an improved peripheral device forming part of an automated system for gates, doors and main entrances. These systems generally envisage the use of various control devices (CD), such as remote control units, digital keypads, transponder card readers or key-operated selectors.

Sending of the information and the commands by a CD may be performed by cable or via radio-frequency signals. Commonly a control unit is equipped with a microprocessor which receives the commands or the signals from a CD and checks whether the command corresponds to a possible action /authorization. If this proves to be the case, the microprocessor "orders" the corresponding action to be performed. The command or signal is simply a code, stored in the memory associated with the microprocessor, corresponding to a precise and unique action.

The techniques for transmission between a CD and control unit involve varying arrangements, costs and technology. In the case of radio commands, techniques for protecting radio-frequency transmission, involving encrypting of the signal, also in variable manner (rolling codes), are used, since the radio signal in theory can be intercepted by anybody. In the case of commands sent by cable, a CD sends to the control unit data representing information which the CD "reads" or "senses". For example, a transponder reader reads the code associated with the card and sends the code read to the control unit where the microprocessor "checks" whether the code read is enabled or not for a certain type of action, or a digital keypad sends the numerical sequence keyed-in to the control unit where the microprocessor "checks" whether the numerical sequence keyed-in is enabled or not for a certain type of action. Therefore the control unit is usually located in a position far from the CD in a location which is "safe" and difficult for access by unauthorised personnel.

Recent safety regulations for automated systems require increasingly more efficient response times and performance features. Therefore, the number of peripheral devices in the systems have increased and, in order to reduce the complexity thereof, a bus line is adopted to connect together all the components of the actuating system, with the aim of reducing at least the number of cables used, allowing simple, fast and low-cost installation.

The disadvantage of bus systems is precisely the bus because, being in the form of a distributed network, it can be easily accessed, in particular from several points. For example, it is sufficient to disassemble a photocell which is connected to the bus, in order to have free access to the data on the bus along which the signal for opening a CD such as a key-operated

selector, a digital keypad or a transponder card reader is also sent; these devices have an internal microprocessor which interprets the code entered (via a keypad) or the code of the transponder card and sends to the motor control unit an original "open" or "close" command (after the control unit has verified the enabled command). In other words, processing of the information entered by the user or data acquired from a user-interface is performed in the

CD and the result of processing is sent to the control unit. Intrusion may occur, for example, in a bus system where it is sufficient for an ill-intentioned person to remove the digital keypad from its mount and replace it with his/her own keypad of the same type (having a known numerical access sequence) in order to be able to control freely the automated system. The same ill-intentioned person may easily access the bus network and the information passing within it, via one of the photocells, via the flashing lamp or via a sensing edge, from any one of the components in the system.

The object of the invention is to solve this situation of potential lack of security. This object is achieved with a control device forming part of an automated system for gates, doors and main entrances, designed to transmit on a bus line a signal resulting from the processing of information entered by a user or data acquired from a user-interface, characterized in that it comprises signal processing means for introducing an identification code into signal prior to sending on the bus.

Preferably said means are designed to send said code to the control unit with each transmission. Preferably this identification code is associated in a permanent and indelible manner with the CD (for example fixed in a ROM), such that it cannot be replaced or modified, while the CD may be replaced only during a new installation operation, which it is assumed is performed by authorised persons. New installation will involve a procedure for recognition/identification of all the devices installed. Said identification code may be assigned to each device during production.

Advantageously encoding and/or reprogramming means may be envisaged for assigning to the CD an identification code which varies with each transmission in accordance with a logic which is also known by the receiver (rolling code).