Serial Port Problems - Epson NX Service Manual

Serial Port Problems

If there is a problem using a serial device from a serial port, follow the suggestions below:
Make sure the device has power and is properly connected to the computer.
Check the device's manual for any DIP switch or control panel settings. The baud
rate, parity, and number of stop bits of the device and serial port must match.
Try a different cable. Also, make sure you are using a null modem cable if the device
is a serial printer.
Check the primary and secondary port settings in the SETUP program to make sure
they are correct.
Run the Serial port Diagnostics test.
Replace the system board. Connectors CN4 and CN8 or the serial port controller in the
F82C711 gate array may be faulty. Authorized service centers outside the U.S. can
replace the gate array chip or connector.
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Figure 2-8 Serial Port Problems