There are three main buffers: b atch, format, and graphic. The
printer also has a 1024 byte i nput buffer which holds data until
it is processed into the respec tive buffer(s).
Data Flow Control
The printer uses Xon/Xoff or dat a terminal ready (DTR) for
data flow control. DTR flow control is usually requi red if you
are using an IBM-PC, unless the PC has a special Xon-Xoff
program.
In DTR mode, the printe r activates DTR when the printer can
accept more data from the host and deactivates when the
printer’s receive buffer is nearly full. In Xon/X off Mode, the
printer sends the Xon character when the printer can accept
more data and sends Xoff when the printer buffer is nearly fu ll.
In either mode, once the print er has indicated that its buffer i s
nearly full (by sending Xoff or deactivating DTR), up to 134
additional characters may be accepted without losing any data.
The printer does not require any hardware or software signals
from the host system in order to operate.
NOTE: Flow control characters can be changed offline
through the Printer Configuration mode.
The total number of formats, bat ches, and graphics is only
limited by the amount of memory available.
9400 Series Programmer’s Manual
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