Electrically programmable transceiver security system and integrated circuit

An electrically programmable security system comprising:

• (a) a receiver responsive to particular radio frequency signals which include a predetermined digital code encoded on the radio frequency signal, said receiver generating a control signal upon detecting the presence of the encoded radio frequency signal, said receiver including means for digitally communicating said predetermined digital code on a communication link;
• and
• (b) a transmitter including non-volatile and updatable memory means for storing a digital code and at least one configuration bit, said transmitter including means for generating a radio frequency signal at a radio frequency to which said receiver is responsive, the radio frequency signal generated by said transmitter being encoded with the digital code stored in said means for storing, said transmitter further including means for coupling with said communication link and means for inputting the predetermined digital code from said receiver unit communicated on said communication link into said means for storing, said inputting means including means responsive to (i) the application of power to said transmitter unit and (ii) the presence of a digital signal at said coupling means for placing said transmitter into a programming mode of operation during which the means for storing is updated with the digital code and said at least one configuration bit communicated on said communication link and further responsive to the non-presence of the digital signal at said coupling means within a short period of item after the application of power for placing said transmitter into a normal mode of operation during which the encoded radio frequency signal is broadcast for a period of time depending upon the state of said at least one configuration bit.

An integrated circuit for use in a security system, said integrated circuit comprising:

• (a) non-volatile updatable memory means for storing a digital code and at least one configuration bit;
• (b) means for communicating said digital code externally of said integrated circuit in a format dependent upon the state of said configuration bit;
• and
• (c) means for receiving a digital code and said at least one configuration bit from an external source and for replacing the contents of said memory with the received digital code and the received configuration bit.

A method of programming a security system, said method comprising the steps of:

• (a) providing a receiver unit which is responsive to a digitally encoded signal and having means for storing the digital code therein;
• (b) providing a transmitter unit which transmits the digitally encoded signal and having means for storing the digital code therein;
• (c) continuously communicating the digital code stored in the storing means of the receiver unit over a coaxial communication link, said coaxial communication link having a shield which serves as an antenna for said receiver unit;
• (d) coupling said transmitter unit to said coaxial link;
• and
• (e) updating the contents of the storing means of the transmitter unit with the digital code communicated over the communication link.

A method of operating and updating a memory used to store a digital code and at least a configuration bit on an integrated circuit, said method comprising the steps of:

• (a) communicating said digital code externally of said integrated circuit;
• (b) receiving a digital code from an external source and comparing the received digital code with the contents of said memory;
• (c) receiving an updated digital code from an external source;
• (d) replacing the contents of said memory with the received digital code and said configuration bit;
• (e) timing each application of electrical power to said integrated circuit;
• (f) enabling and disabling said replacing step during a predetermined time period after each application of electrical power to said integrated;
• and
• (g) communicating said digital code after step (f) for a period of time the length of which is controlled by the state of said at least one configuration bit.