Datamax-O'Neil Class Series II Programmer’s Manual - Manual (Page 283)

Appendix J – General Purpose Input Output Port Applications
Class Series 2 Programmer’s Manual 269
MII Sample SOP Circuit
Pin 3 should be pulled to +5VDC. In additional,
connections for the external Start of Print control can
either be directly made to Pin 4 of the Option Port (or
Main PCB connector) using a TTL-level input, or via an
interface circuit (similar to the one shown). For more
information, see the table below.
1
8
Vcc
Gnd
GPIO Connector Pin Number
3 Spare
4 SOP
1K O
1K O