I want to hook up my GPS 72 to my laptop via a USB port. Garmin only sells serial 9 pin cables then you have to go to an adaptor cable to get USB. BUT there is no power on a 9 pin serial port. I would like to get power so that batteries won't be an issue. The USB is a 5 V supply garmin say 8 or more volts BUT the unit runs on two AA batteries providing about 3 V. What to do???? My other Garmin is rigged to the VHF and uses the boats batteries. Is 5 V from the laptop enough voltage??? Is 100mA enough current?? Life would be much simpler and much less expensive if Garmin just sold a USB connector cable. But they don't I guess that they do the math and have decided that they would rather sell two $40 cables instead of just one.
Garmin GPS 72 Power Suppy
- Thread starter MoonSailer
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I had the same issue with my GPS12. Both of these units use the same 4-pin male jack on the back of the GPS. So I did some investigating and found a home made power supply for the GPS12. I never built it but instead got a unit from Radio Shack. But what about the 4-pin jack?
Garrmin sells them connected to a cable. But they were costly. So more reasearch netted this site: http://www.pfranc.com/projects/g45contr/g45_idx.htm and here is the link to the DIY power supply if you want to build one: http://www.milair.co.uk/adapt.html
You send them a donation and they send you a plug. I got two of them and one is currently on the boat with the Radio Shack supply. This is connected to my autopilot power source and it works great.
Good luck.
Garrmin sells them connected to a cable. But they were costly. So more reasearch netted this site: http://www.pfranc.com/projects/g45contr/g45_idx.htm and here is the link to the DIY power supply if you want to build one: http://www.milair.co.uk/adapt.html
You send them a donation and they send you a plug. I got two of them and one is currently on the boat with the Radio Shack supply. This is connected to my autopilot power source and it works great.
Good luck.
The older Garmins with the four pin, round NMEA 0183 port are capable of running on voltages ranging from 9-48 VDC. The newer ones, with five or more pins, are usually capable of running on 9–36 VDC. This is part of the NMEA 0183 specification IIRC.
The problem with using Garmin's USB connector is that most software, other than Garmin's own, doesn't recognize the Garmin data protocol the USB port is stuck using. WHen using a serial port on a Garmin, you do have to make sure it is set for NMEA 0183 with the following settings: 4800 baud, 8 bits, No parity, 1 stop bit.
To use their four-wire cable for both data and power, you have to hook up the TX and RX wires to pins 2 & 3, the ground to pin 5 and the DC ground as well, and the power cable to the +12 VDC source. If you don't hook up the ground wire to Pin 5 on the serial cable DB 9 connecter, the GPS can't be read by the computer. If you don't hook up the ground wire to the DC ground, the GPS won't accept external power.
The problem with using Garmin's USB connector is that most software, other than Garmin's own, doesn't recognize the Garmin data protocol the USB port is stuck using. WHen using a serial port on a Garmin, you do have to make sure it is set for NMEA 0183 with the following settings: 4800 baud, 8 bits, No parity, 1 stop bit.
To use their four-wire cable for both data and power, you have to hook up the TX and RX wires to pins 2 & 3, the ground to pin 5 and the DC ground as well, and the power cable to the +12 VDC source. If you don't hook up the ground wire to Pin 5 on the serial cable DB 9 connecter, the GPS can't be read by the computer. If you don't hook up the ground wire to the DC ground, the GPS won't accept external power.
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