Isuzu 1999 RODEO Workshop Manual page 1899

7A1–20 TRANSMISSION CONTROL SYSTEM (4L30–E)
C07RT006
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
communication on the data line at the same time, only the
higher priority message will continue. The device with the
lower priority message must wait.
NOTE: The Class 2 data wire is always terminal 2 of the
new 16–terminal Data Link Connector (DLC).
16 – Terminal Data Link Connector (DLC)
OBD II standardizes Data Link Connector (DLC)
configurations. The DLC, formerly referred to as the
ALDL, will be a 16–terminal connector found on the lower
left side of the driver's side instrument panel. All
manufacturers must conform to this 16–terminal
826RW002
standard.