QMS 1725E, Reference

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Parallel
Interface Modes
5-25 Additional Technical Information
trailers. The print server does not necessarily send multiple print jobs
to the printer in the order that you queued them to the printer. The
network job separator is accessed with each print job, so this ensures
that network job separation is enforced. See
QMS Crown Network
Notes for more information on how to create a network job separator
for several commonly used networks.
Parallel Interface Modes
In addition to the Centronics parallel interface, your printer provides
IEEE1284 bidirectional parallel interface, which supports five modes
of operation. Although the printer automatically recognizes and uses
the mode dictated by the host, the modes can be set manually
through the printer control panel. See chapter 4, “Printer Configura-
tion,” for information on manually selecting modes through the control
panel.
Byte Mode
Printer-host parallel communication is done in bytes.The byte mode
may be used by the host device in a DMA (Direct Memory Access)
mode for more efficient operation.
When byte transfer is complete and there is no more data to transmit,
the host may do one of the following:
n
Terminate and return to the compatibility mode.
n
Stay in the Host Busy, Data Not Available phase.
n
Set Host Busy Low, putting the interface into the idle phase.
If there is additional data, the host may do one of the following:
n
Set Host Busy Low, indicating that the host can accept additional
data.
n
Stay in the Host Busy, Data Not Available phase.
n
Terminate and return to the compatibility mode.