Connect Garmin 18x 5hz GPS to computer via USB Cable

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Joined: Mon Nov 13, 2017 8:00 am

Connect Garmin 18x 5hz GPS to computer via USB Cable

Postby vivitern » Mon Nov 13, 2017 8:05 am

I want to connect Garmin 18x 5hz GPSto computer via FTDI Serial
TTL-232R-3V3-WE USB Cable (this: But once I try to update the GPS via Garmin updater, I get framing error. "A communications error has occured. The hardware detected a framing error. Please ensure that the GARMIN device's Interface option is set to GARMIN or Host mode and try again."

This happens after I have chosen COM port and baud rate and click "OK" in the updater. I am not sure which baud rate I should use but Garming gives me 5 options in the updater (9600, 19200, 38400, 57600, 115200) and none of them work.

I have connected every wire individually, both GPS grounding wires into adapters grounding wire (blacks together), GPS' TXD into adapters RXD (white to yellow), GPS' RXD (RCV) into adapters TXD (green to orange) and red power cables together. Now after updating the adapters drivers and connecting the cable the adapters starts to flash green light (but not red). When I run the GPS updater the green light starts to flash for few seconds and then shuts off and error message pops up.

Is my wiring the problem (I just pushed the wires inside the other end of the adapter) or is the problem software side? Any suggestions or tips how I can connect the 18x 5hz through USB port?


Thank you Andrew!

Now I need new adapter or MAX232 (or similar). Problem is the Garmin 18x 5hz only has cables on the other end that I can't connect to typical adapter. I have one serial port (RS232) to USB adapter lying around somwhere. I try to hook it up somehow into the Garmin and post results. I lack any soldering equipment or experience really...


I tried out the FT Prog and inverted the RXD and TXD signals but I still get the same problems as before. I also tried to invert every signal. After that did not work out either I dug up an old USB to RS-232 converter, but as I predicted, I really have no way to connect the Garmin GPS and typical RS-232 male port.

So either the problem lies in the GPS it self or the connections, because inverting the signals did not work. Thank you for the help!

Posts: 1
Joined: Thu Jan 04, 2018 5:52 pm

Re: Connect Garmin 18x 5hz GPS to computer via USB Cable

Postby NealXu » Thu Jan 04, 2018 6:06 pm

Hi...I bought a garmin18 5Hz, but what I didn't know is that it comes without the serial plug but with a free wire that you have to connect to a serial plug.So I looked for the wiring diagram and then I welded the wires to the serial plug. The problem is that this device can't receive power supply by the
serial port because it hasn't got enough amperage; so, a friend of mine who is quite skilled in electronics suggested me to use the usb port as power
supply, so i connected the black and the red wires with the ones of the usb.

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