The KAD/FBM/103 monitors FireWire (IEEE 1394b) traffic. It acts as a leaf in the FireWire bus topology and to all other nodes on the bus, the link layer and transaction layer appear to be deactivated. The KAD/FBM/103 parses isochronous or asynchronous stream packets. All other traffic is ignored (configuration traffic, PHY packets, and asynchronous transactions). Selected packets and associated tag information are stored in one of 65 triple-buffered parser slots. Each parser slot contains up to 1036 16-bit words: 1030 words of packet content; three words of timestamp information; one word containing the transaction number; one word containing the packet size; and one word containing buffer information.

FireWire packets are parsed in two stages. First, packets are filtered to accept only isochronous and asynchronous stream packets (traffic with transaction code A16). Then the channel ID and message ID (third quadlet in the FireWire packet) are used to classify the packet and determine which of the 65 parser slots the packet is written to. Unique channel ID and message ID combinations can be targeted to any of the 64 available parser slots. Parser slot 0 may be configured to operate as a "catch all" slot where any channel and message IDs not mapped to specific parser slots will be routed.