Connecting a Global Positioning System (GPS) using RS-232

[Jawahar]

I have a GPS unit (Garmin Etrex Legend) that supports RS-232/NMEA-0183 communication.

How do I connect it to J4 module on my IsoPod V2?

[nmitech]

Can you post the link to your GPS unit? I Need to take a look at the product spec. Thanks!

[Jawahar]

Here are the links....

1. Product Manual:
http://www.garmin.com/manuals/eTrexLegend_OwnersManual.pdf

2. Specifications:
http://www.garmin.com/products/etrexLegend/spec.html

From the unit, there are four lines coming out (Data In, Data Out, Ground, Power).

Thanks

[nmitech]

The serial I/O on the eTrex Legend Unit are RS-232 comapatible as said on page 58 in the manual. So the wires should connect as below,

----eTrex--------------J4, IsoPod
GND (black)----------Pin 5 (GND)
Data Out (white)----Pin 7 (SIN1)
Data In (green)------Pin 9 (SOUT1)

[Jawahar]

Okay. I'll give it a shot and get back.

Thanks!

[Jawahar]

Dr. Huff thinks that the RS-232 voltage level at 'J4' of the Pod, unlike voltage level at 'J1', may not match up to that of the GPS unit.

Is that true?

[nmitech]

On IsoPod V2 , both SCI drivers on J1 & J4 are configured for RS-232 by default.

On IsoPod V1, SCI0 signal on J1 is dedicated for RS-232, J4 is dedicated for RS-422 driver.

Yours should be ok if you have IsoPod V2

[Jawahar]

Thanks! I ll get back if I need to.