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Old 14th Feb 2021, 3:12 pm   #12
mole42uk
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Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,588
Default Re: Help with RS232 needed!

Quote:
Originally Posted by ColinB View Post
Link the TX and RX pins of the USB to serial cable (with the cable disconnected from the far-end device!) This is pins 2 and 3 on a DB9 cable, from memory.

In the terminal program can you type characters and see them echoed back to the screen? If so, the USB to serial cable, the OS and the driver are working (assuming no hardware handshaking etc).
That works! I get characters echoed back but with two rubbish characters on the end - that must be the CR & LF characters.
So, if the cable and adapter is okay, then the output from the GPS must be awry.
Perhaps I'll put an inverter in the signal.

I wonder if the TXD and RXD pins in the GPS device are wrong way around, would that have this effect? Data Out from the GPS receiver is connected via a MAX233 to RXD, Data In is connected to TXD
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