ÛZIATECH
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9. PARALLEL PRINTER PORT INTERFACE
The ZT 8907 supports a Centronics™-compatible printer port interface, available
through connector J9. The printer port is configurable for normal ("nibble mode") or
extended ("bi-directional mode") through screen 2 of the BIOS SETUP utility.
The ZT 90157 cable assembly (shown in the "
" section in Appendix B) allows the
onboard LPT1 channel to be interfaced directly to 25-pin D-Shell parallel port devices,
as used in PC applications. The onboard port may be disabled through screen 2 of the
BIOS SETUP utility to allow use of STD 32 based parallel interfaces.
PARALLEL PRINTER PORT CONFIGURATION OPTIONS
The different modes for the printer port are described below. Details for the parallel port
on the ZT 8907 are discussed in the following topics. Shown in parenthesis is the
description for each of the modes as presented in screen 2 of the BIOS SETUP utility.
Parallel Port Mode Description
Max. Data Rate
Compatibility
(Normal)
Uni-directional data configuration. The original
PC-AT Mode. Also known as "nibble mode"
because the four status bits in the cable are
used for feedback from devices such as tape
back-up units (when restoring data from a
tape). Software based protocol.
50-150 Kbits/s
Extended
(Ext)
Bi-directional data transfer capability. Similar
to Compatibility mode, but allows 8-bit data in
both directions; faster for interfaces needing
to supply data to the computer (such as
scanners, tape back-up); software based
protocol.
50-150 Kbits/s
ADDRESS MAPPING
The address mapping for the PC standard architecture and the ZT 8907 is shown
below. The onboard port may be disabled through screen 2 of the BIOS SETUP utility to
allow an STD 32 LPT port to be used.
Parallel Port
PC Port Address
ZT 8907 Port Address
LPT1
3BC (typically)
378-37B - Compatibility, Extended