The KAD/MSB/103 is a MIL-STD-1553 dual redundant bus monitor which combines the capabilities of a SNARFER, coherent message PARSER, message counter, and error detection functions on a single module. Traffic refers to words on the bus (command, status, and data) and tags refer to associated information (microsecond time of sync. bit transition, message count, response time, and errors).

When used in PARSER mode, the KAD/MSB/103 triple buffers up to 1,023 complete messages and their associated tags in buffers up to 43 words wide. The INFO tag associated with each message has a stale bit (message read before), a skipped bit (buffer overwritten), and an empty bit (message was never received), as well as an indication on which bus the message was received. The MESSAGE count increments on receipt of a valid message. The ERROR word has bits indicating the type of error caught in the form of a 6-bit code and the bus on which it occurred. The KAD/MSB/103 records Mode Code 17, sub-address map numbers for each remote terminal separately. With that, it can monitor the full expanded sub-address space for up to 31 remote terminals. The SNARFER stores selected traffic and tags in a FIFO 3K words deep.

Each word has 16 bits for traffic/tag information and 8 bits for FIFO content identification. Data selection and content identification is based on the bus (primary/secondary), traffic type (command, status, data), tag type (high/low/micro/response time, message count) and how full the FIFO is.