Troubleshooting | Black Box IC171C manual

RS422/485 SERIAL INTERFACE PLUS

7. Troubleshooting

Computer does not recognize any COM ports, or the system is “dead” or non-responsive.

How to identify the problem: Use the SSD.COM Program (found on your utility diskette).

Solution: Identify all COM ports installed on you computer and address the RS422/485 Serial Interface Plus at a different address from those already present.

Reason: Only one device can occupy an address location. If more than one device tries to share an address space, a conflict will occur, preventing either device from working.

The RS422/485 Serial Interface Plus’s address is not recognized by the system.

How to identify the problem: Use the SSD.COM Program (found on your utility diskette).

Solution: Verify that the RS422/485 Serial Interface Plus addresses are correctly set.

Reason: If the board is incorrectly addressed, your application will not respond.

The RS422/485 Serial Interface Plus transmits but does not receive. The other side appears to receive, but you do not receive any characters in your application.

How to identify the problem: Verify that the IRQ is set properly on your RS422/485 Serial Interface Plus and is correctly set in your application program.

Solution: Change the IRQs so that they are correct.

Reason: Most DOS application programs are “interrupt-driven” on receive. If the IRQ is not set on the card to match those required by your application, it will not receive characters, because the interrupt for the first character cannot be serviced.