Most MIL-STD-1553 systems use the 1553B protocol, but systems do still exist that use the older 1553A protocol or the MDC-A3818 protocol (used on F18). The purpose of this Application Note is to explain how to use Abaco products with the 1553A or MDC-A3818 protocols. This Application Note assumes a basic knowledge of 1553. For information on the MIL-STD-1553 protocol refer to the “MIL-STD-1553 Tutorial” document available from Abaco Systems. Additional information can also be found in MIL-HDBK-1553A.