Section 7.1.14 isn clear. How long can dribble and an EOP be?
Dribble is between 0 and 15ns per hub and the change in delay for the drive to J at the end of the EOP to -0/+15ns. If the delays for J/K to EOP and the EOP to J transitions are identical, the EOP’s width won’t change. If the EOP to J transition has greater delay than J/K to EOP, the EOP will lengthen, and it will shrink in the opposite case—the worst cases are with 0ns dribble and 15ns extra EOP to J delay and with 15ns dribble and 0ns extra EOP to J delay. Thus, the width of the EOP can change by up to 15ns per hub, or 75ns with 5 hubs in series. In shorthand, this is often referred to by saying the EOP width is between 1 and 3 bit times, though that’s not technically correct. The USB-IF strongly recommends all device receivers be checked to make sure they can handle the full range of dribble and changes in EOP width-failure to handle this correctly is the leading cause of device failures on long USB busses.
