Tally T2265 SprintPro, Maintenance Manual

Page: 43 / 178

General infomation
about external
interfaces
This printer has a bi-directional parallel Centronics type interface (according
IEEE1284) which is mounted on the printer’s main board. As an option, the plug-in
interfaces of other pay be used. E.g. if someone wants to use an (optional) RS232
(V24) I/O he has to use the combined MT3x0 serial/parallel I/O. Since this I/O also
has an on-board Centronics type interface the built in interface must be switched off.
(Please consider that there are interfaces without a parallel interface; i.e. TTY,
RS422. Using this kind of interfaces will not switch off the bi-directional I/O.)
If an additional parallel I/O is added, it is mandatory to disable the internal CX
I/O on the main board, so that only the plugged-in parallel I/O’s will be active.
Otherwise the printer will misread data on the parallel data lines.
A shared serial/parallel (RS232(CX) I/O is possible, but two parallel I/O’s are not
allowed. To avoid this the CPU of this printer is monitoring a signal at the connector
for external I/O’s to determine the presence of an additional to the standard parallel
I/O on the main board. The signal’s name is PT0, it can be found at Pin 15 A of the
external I/O connector. Please refer to the following table to determine the function of
PT0:
PTO in Volts Meaning
< 1.8 Volt the internal parallel (CX) I/O will be used
> 1.8 Volt
…
2.5
…
< 3.0 Volt the external parallel I/O will be used*
> 4.5 Volt the internal parallel (CX) I/O will be used
* Please consider that the external parallel interface may not support IEEE1284 (plug’n’play).
Possible modification of existing and future external I/O’s with own parallel interface:
V
CC
4k7 pull up
4k7 pull down
GND
PT0
Functional Description Electronic Functions
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