Canon PC-D320 Service Manual page 25

Encoding/Decoding the Data
In USB, data transfer lines are ultimately encoded with NRZI (Non Return to Zero Invert)
method. When the original data bit is 0, sent data bits are inverted; when the original data
bit is 1, the value is retained.
However, if the level of the transferred data remain unchanged for a certain period of time,
the receiving side may not be able to synchronize with the data sample position, which
will result in data bits being out of phase. This is prevented by a method called bit stuffing;
when data bit 1 is repeated 6 times, one 0 bit is added to the original data before encoded
with NRZI.
0
Data
Idle
NRZI
Idle
Supported Software
The following table shows the relationship between available drivers and the interfaces for
this model.
Windows 95
Windows 98
Windows NT 4.0
Windows 2000
Windows Me
Windows XP
*: A USB connection applies to Windows XP/Me/2000 pre-install models and to
pre-install models upgraded to Windows XP/Me/2000 from Windows 98 or later.
Windows Drivers
Win98.Me LBP Printer Driver (USB supported)
Win2000.XP LBP Printer Driver (USB supported)
PC-D320/PC-D340/FAX-L400 Chapter 1: General Description
1 1 0 1 0 1
Figure 1-5 NRZI
D320/D340/L400 Suite
Suite USB I/F
not
supported
conditionally
supported*
not
supported
conditionally
supported*
conditionally
supported*
conditionally
supported*
1-15
0 0 0 1 0 0 1 1 0