Class 2

Fig 1: Identifying CLASS 2 Pulse Width

Courtesy of ISUZU MOTOR CO.

Class 2 data is also pulse width modulated. Each bit of information can have one of two lengths: long or short. On the other hand, UART data bits come in only one length (short). The pulse width modulation of Class 2 data allows better utilization of the data line.

The message carried on Class 2 data streams are also prioritized. This means that if two devices try to communicate on the data line at the same time, only the higher priority message will continue. The device with the lower priority message must wait.