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Serial Adapter Pin-Out


New Member
Greetings all,
I need to wire a DB-9 connector so I can provide power to the serial-to-1wire adapter. The documentation states that the DS9097U uses RTS and DTR as power pins, but I'm getting myself twisted up on what pin numbers are used on the adapter's DB-9F connector.

Is the DS9097U wired as DCE, requiring a direct connection to the host's (PC, Rabbit, Mac etc.) DTE-wired DB-9 connector? Or is it wired as DTE requiring a "standard" null-modem connector?

IOW --- is the adapter's DB-9F wired to expect RTS on pin 7 or pin 8? (And similarly, DTR on pin 4 or pin 6?)

I've got a feeling that I'm going to feel very dull-witted very shortly! :D Ah, well --- won't the first time, or the last time!

Tim "fussing over minutae" Cole
Ottawa, ON


Active Member

Here are the pinouts of the DS9097U TXD (3), RXD (2), DTR (4), RTS (7),
PC-Ground (5).

It should just use a straight through serial cable.