Tally T5023+ Programming Manual page 393

Appendix
nPeriphRequest / nFault
Compatibility Mode:
ECP Mode:
Epson ANSI:
1284 Active / nSelectIn
Compatibility Mode:
ECP Mode:
Description of the physical interface
(Printer driven)
Set 'low' by the printer to indicate that an error
has occoured.
The printer may drive this pin 'low' to request
communications with the host. The request is
merely a 'hint' to the host; the host has ultimate
control over the transfer direction.
nFault = 0: ERROR status
nFault = 1: ONLINE and STOP status
(Host driven)
Set 'low' by host to select the printer.
Driven 'high' by the host while in ECP Mode.
Set 'low' by the host to terminate ECP Mode
and return the link to the Compatibility Mode.
T5023/5023+ - Programming Guide
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