programming the universal transmitter according to the invention will be described with respect to a three switch transmitter i e one which can operate up to three receivers to assist in programming the transmitter for operation a table of known manufacturer 39 s along with their particular frequency of transmission is stored in memory of the microcontroller 12 for example the transmitter may be programmed to operate stanley multi code linear sears chamberlain lift master genie with nine code switches and genie with twelve code switches a number is assigned to each manufacturer which number is used by the microcontroller 12 to determine which frequency to use for transmission for example stanley is assigned 1 multi code is assigned 2 linear is assigned 3 sears chamberlain and lift master are assigned 4 genie receives with nine code switches is assigned 5 and genie receives with twelve code switches are assigned 6 the universal transmitter must be programmed with both a frequency and a code before it will operate to program the universal transmitter with a code the user must determine the code of the transmitter of his present system for systems with code switches the user simply records the position of each switch if the user 39 s present system employs a learning receiver i e a receiver.