Microcom 334M Operator's Manual page 96

Chapter 5
NOTE: A status request (^E, ^D5, or 5 NULL's 01) will never show the
status of the outputs while a status request will show the input status if:
1) GP I/O is enabled AND
2) One or more bits have been configured to generate errors when
active AND
3) One or more of those halting bits have gone active and have
produced an error that has not been cleared.
NOTE: If the printer is not in the general purpose I/O mode, the inputs
status may still be read with the ^D150 command but the outputs
cannot be read (or written to) with the ^D69 or ^D68 commands.
NOTE: If an input has caused an error to be generated, then goes
inactive, and another print request received before the error is cleared,
the printer will not print and will remain in the error state. A status
request will show the active error inputs. This condition will remain until
the error is cleared.
NOTE: Default power up will disable I/O mode.
The P17 and P21 connectors are 8 pin Molex part number #51021-
0800 and Microcom Corporation part number 510129-0008.
The pin out is as follows (the square pad denotes pin one on the PCB):
Connector P17 is the input port.
Input high = 15 to 30 VDC; 24 VDC Nominal
Input low = 0 to 6VDC
Input impedance = 115Kohm (to ground)
Connector P21 is the output port.
Output high = 24 VDC +/- 10%, Max Voltage applied = 28VDC
334M Operator's Manual - 880060-0110
1 = ground
2 = g/p input 1 - Print
3 = ground
4 = g/p input 2 - Print Test Pattern
5 = ground
6 = g/p input 3 - Reset
7 = ground
8 = g/p input 4
1 = ground
2 = g/p output 1 - In Reset or printing
3 = ground
4 = g/p output 2 - Error
5 = ground
6 = g/p output 3 - Downloading a format
7 = ground
8 = g/p output 4 - Format loaded
Printer Commands
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