Abstract: A method of installing a security system includes transmitting an air-borne request signal to a security device. An air-borne reply signal is transmitted from the device in response to the request signal. The reply signal includes identification information corresponding to the device.

Abstract: A high speed shift register device includes first and second shift registers. Odd numbered bits of a word are stored in the first shift register and even numbered bits of the word are stored in the second shift register. The first shift register is clocked by a clock signal, and the second shift register is clocked by the complement of the clock signal. The outputs of the first and second shift registers are alternately shifted by means of a multiplexer to an output conductor. A control input of the multiplexer is connected to the clock input. Data is shifted out of the multiplexer at a rate which is twice the normal shifting rate of each of the first and second shift registers.