635 and external RS232?


New member
I am trying to connect my laptop via RS232 using a DB9 cable to a 635 display.

I am using a straight through serial cable to the PC.

I made a cable identical to the WR232Y08; and I added +5V from an external DC supply to pin 4 on C2, and ground from the same external DC supply to pin 5 on C2.

I can't get the PC to talk to the display (WinTest says "Looking for module..."), and the terminal program won't talk to it either (no response from the 635). I'm not sure what the problem is.

I have verified that the serial port on the PC is working (made a loopback cable and used a terminal program to echo back the strings I send).

Any ideas?

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