The PacketType indicates whether the packet is a command (Command) or a telemetry (Data) packet.
The secondary header flag indicates whether there is another header following the primary header (Present) or not (NotPresent).
The sequence flag indicates the interpretation of the sequence count. Continuation- the sequence count indicates the block in a series of packets containing segmented data FirstSegement- the packet is the first in a series of segemented packets. LastSegement- the packet is the last in a series of segemented packets. Unsegmented- the sequence count is an incrementing counter used to distinguish packets.