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Version 1.73 Copyright © 1997 Link Communications Inc. 1/18/97
The SPI Serial Format:
There is another type of serial protocol that is totally unrelated to RS-232. It is used for
controlling some remote base interfaces, such as the Doug Hall RBI-1, RLC-ICM and BCD
radio interfaces. Instead of using a data in and data out line like RS-232, it uses two lines for
output: data out and clock out. There is no input to the controller; data is transferred only one
way. Since there is a clock line, there is no need to specify a baud rate (although there are a
few timing restrictions). The RLC-Club uses the output lines on the optional Deluxe board to
send this type of serial. It is sent automatically by the RBI-1 / RLC-ICM commands and can be
sent manually using command 138. Remember that the outputs are open collector and require
pullup resistors (pullups are built into the RBI-1 and RLC-ICM).