A Field is the smallest unit of information your plug-in can display. It might be derived from a single bit (ACK/NAK, Rd/Wt), multiple bits or even multiple bytes/symbols/characters. For example, you might emit a field called 'SYNC' whenever you see 10 or more 0x55 in a row or an extended quiet period. It's up to you. A field starts at the indicated timestamp and extends until the next field is received.