SATO CL 408e - Manual (Page 63)

Page 3-3
Section 3. Interface Specifications
SATO CL408e/CL412e Service Manual PN 9001078
Rev. B
3.3 The Receive Buffer
The CL408e/CL412e printers have the ability to receive a data stream from the host in
one of two ways. The receive buffer may be configured to accept one print job at a
time or multiple print jobs. The single job print buffer is generally used by software
programs that wish to maintain control of the job print queue so that it can move a
high priority job in front of ones of lesser importance. The multiple job buffer on the
other hand prints all jobs in the order they are received by the printer and the order of
printing cannot be changed.
Single Job Buffer
The printer receives and prints one job at a time. Each job must not exceed 2.95MB.
Multi Job Buffer
The printer is able to continuously receive print jobs, compiling and printing other jobs
at the same time. It acts much like a "print buffer" ot maximize the performance of the
host and the printer.
When using the RS232 Serial interface, the Multi Job Buffer uses either the Ready/
Busy with DTR (pin 20) or X-On/X-Off flow control protocols. See these sections
for more details. With an empty receiving buffer, the status of DTR is "high" (or an X-
On status if using X-On/X-Off), meaning the printer is ready to receive data. When
the receive buffer is holding 2.0MB of data (1MB from being full), DTR will go "low"
(or an X-Off is sent) indicating the printer can no longer receive data. This condition
is called "Buffer Near Full"
DTR High
or
X-On
The receiving buffer will not be able to receive more data again until a "Buffer Available"
condition occurs. This takes place when the receiving buffer has emptied so that only 1MB
bytes of data are being held (2.0MB bytes from being full). At this time, DTR will go "high"
or an X-On is sent to tell the host that it can again receive data.
0
2.0 MB 2.95MB
Buffer Near Full
DTR Low
or
X-Off