DSC Icom 421 & Garmin 178c

[pettal]

Hi All,

Finally got our MMSI through today and have a couple of questions if anyone can help it is much appreciated. I know this one has been done to death on various different systems, but help still apreciated!!!

Firstly on my Icom 421 it says no GPS or something like that, am I to assume that this means the cable hasn't been connected between the two units?

If that is the case then I read that the Icom (quite handily) has a GPS jack although the Garmin doesn't. Can I just snip off the jack and connect the corresponding wires together......or is it best to try and fit the garmin unit with a corresponding jack?

If the fitting of a jack is required for the Garmin then anyone know where I can get one?

If not and I can just attach the corresponding wires to each other then a bit more help is needed! The garmin has two wires (one white - data in) and (one green - data out) which by the diagram I'm looking at are the two needed for the connection. However if I've just snipped the jack off the Icom I'm not sure which is which?!

Thanks once again for any help!

Ta

Pettal

[Jimbob]

I posted thsi sometime ago, it does not answer all the questions but i think i have the answers you need, give me a call 01628432996, its easier

Hi all

Just some helpful info if you are fitting the ICOM DSC M421 to a GSP/ chart plotter

I’m sure this may seem straight forward, but it took me a couple of hrs reading the books

1) Firstly depending on the GSP check that the data speed rate is set at 4800, and the NMEA is 0183 v2.0 3.02. If there are no settings and its fairly new then this should be the output anyway, as example my Raymarine 420 is about 3 years old and has no facility to change.
2) The connections are (switch power off before starting)

a) NMEA data out (Yellow in my case) of the GSP or plotter goes to the NMEA + of the radio, the inner core (White). Do not use the NMEA + from the GPS or plotter
b) The Data out common (brown wire in my case) of the GSP or Plotter Goes to the outer copper cable (seems like the shield). Do not use the NMEA – from the GPS or plotter. There is only one core so again you cannot go wrong.

That’s it, I hope it helps

[pettal]

Thanks jimbob!!

I'd done a search through the electronics section looking for something like that and must have skipped past yours!?

I may give you a tinkle once I'm sat in front of it all and get stuck, although between 4 wires I should be able to manage!

[Swifty]

Normally the Garmin outputs on a multicore cable (about 7 wires I think) one of these is NMEA out. I have a feeling its the dark green but please check it to make sure. This connects strait into the GPS input on the Radio which is normally a 3.5mm jack socket on a (too) short flying lead. The shield of the jack plug goes to earth from the multicore. I will see if I can find the wiring key tomorrow.

If you dont have a jack plug then order one from Maplins or a local hifi shop. Its the same plug as your walkman headphones.

ATB.
Tim.

[pettal]

Thanks for all your help........I've been a bit of a Tw@t.......should have read the manual.........the cables were all connected, I'd just not set the garmin unit to output NMEA! Doh!!!!

I've asked the Misses to beat me this evening with a plank covered in 6 inch nails for my stupidity.

I'm a bad, bad monkey.