The Receive Buffer - SATO CL408 Operator And Technical Reference Manual

Section 5. Interface Specifications

THE RECEIVE BUFFER

The CL 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 64K bytes.
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" to maximize the performance
of the host and the printer.
DTR High
or
X-On
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 62K bytes of data (2K bytes 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" (see figure below).
DTR Low
or
X-Off
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0
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62K 64K
Buffer Near Full
56K 64K
DTR High
Buffer Available
SATO CL Series Printers
DTR Low
or
X-Off
or
X-On