TallyGenicom 2365, Руководство по обслуживанию

Страница: 42 / 184

Electronic Functions Functional Description
3-22
3.3.3.2
General infomation
about external interfaces
This printer type is equipped with a parallel Centronics type interface (according
IEEE1284) and a internal Ethernet Interface which are mounted on the printer’s main
board. An external modular serial Interface can be installed so the printer is able to
handle 3 Interfaces at a time (Parallel, Serial (ext.) and Ethernet (int.)). Other modular
interfaces (TallyCom, TGNet, Coax, Twinax, etc.) will cause the internal parallel I/O
being switched off.
If an additional parallel I/O is installed, it is compulsory to disable the internal CX I/O
on the main board, so that only the plugged-in modular parallel I/O’s shall be active
in order to avoid misreading data on the parallel data lines: Two parallel I/O’s will not
work together.
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 a second parallel interface plugged in the modular
slot.
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:
Possible modification of existing and future external I/O’s with own parallel interface:
PTO in Volts Meaning
< 1.8 Volt
> 1.8 Volt … 2.5 … < 3.0 Volt
> 4.5 Volt
the internal parallel (CX) I/O will be used
the external parallel I/O will be used
the internal parallel (CX) I/O will be used
V
CC
p u ll u p
p u ll down
GND
PT0