Token Frame in 802.5
Start Frame Delimiter (JK0JK000) [1 octet]
Access Control (PPPTMRRR) (T=1 for token frame) [1 octet]
End Frame Delimiter (JK1JK1IE) [1 octet]
PPP gives the priority of the token
T=1 for a token, 0 for a full frame
M is set to 0 by the sending station, to 1 by the monitor station; if the bit is not changed, there has been a problem