I have made it work with a Garmin 72, and adaptor cable, four different laptops, three versions of Windows and five different bits of navigation software, and I'm a dizzy old geezer not a geek. There is absolutely no reason to give up on this. (The details of how to see this differ depending on which version of Windows you are on.) If you can't you need to install the software. You should go into control panel >devices and see if you can see a USB to serial adaptor on a port called 'prolific.whatsit'.

However I'm pretty sure your cable is meant for this unless someone bodged it together (and even one that I bodged together works). It may be that you have to download the software (and you almost certainly can, even if a disk is supplied normally). It came with an installation disk for the software. Garmin does not send USB out of that four pin socket so why make a cable that stuffs it up a USB? The only thing in my cable is a wee black rectangular bit about 30mm by 20mm (and I haven't a clue what's inside it). There would be NO SENSE in making a cable that goes from the Garmin plug to the USB unless it was designed to be a converter. The converter is not some massive lump of hardware. I have got it to work on:Ĭlick to expand.I don't think that's true. If this doesn't get you going, tell me what navigation software you are using and I might be able to help. Instrument will select these speeds, software may need to be set manually. Speed set to 4800 for NMEA or 9600 for Garmin. Make sure software and instrument are set to the same.ģ. On the 72 set it in the 'settings>interfaces menu'. Set the COM port in your nav software to the right number.Ģ. The COM port number - most nav software will help you with this, but look at devices from the control panel to see the number of 'prolific USB to serial'. What navigation software are you using?ġ. I have exactly the same setup as you, and can make it work. If you haven't got that installed you need to do so. It requires the correct software to be installed, but I'm guessing that is what you mean by 'driver'. It sounds like you have a USB to serial adaptor. (NB Garmin 72H does send USB - but it has a separate USB socket.) Click to expand.As has been pointed out, the Garmin 72 does not send USB it sends RS232.

Garmin connect for pc