NMEA yet again

R

Risa

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sorry to bore you all with this but ive trawled previous posts and cant answer the following.

I Have
1 off laptop with no serial port, 1off Magellan 320 ( with serial to usb adapter), a Raymarine st4000+ wheel pilot and a cockpit mounted NASA clipper GPS repeater.

I can currently connect the GPS to the laptop and have that working perfectly no issue here.

I now want to be able to tell the wheelpilot where to go from the laptop/chartplotter AND ( and i know im being greedy now) be able to see course and distance etc etc on the repeater.

The repeater has a cable for connecting to something but has jst bare wires and the wheelpilot has the terminals for NMEA which i can easily connect with some bits of wire.

Im now left with a laptop/chartplotter/gps fully functonal and some bits of cable from the repeater and the pilot.

where do i shove the bits of cable???????

Do I need a multiplexer?????
 
Forget Multiplexers ..... they are boxes to stop talkers interfering with talkers etc. etc.

Your laptop program menu will have another setting specifically for Autohelm instruction. This should be set to on ... and you'll have to tell it what com port the signal is going out on ...

So you can fit a serial plug to the lead from autohelm and then a usb to serial adaptor lead ... plug into pc ... checking the com port it installs to ....

OK thats the simple explanation ...

Join the GPS Nav group and when it doesn't work - there are plenty of people who can advise how to sort it .....

See my signature below and click on the GPS Navigator group ....
 
There are a few problems with feeding Autopilots with signals from USB-Serial converters. The Prolific one is known to have problems, wheras the Keyspan unit is known to work in the majority of cases.
I'ts mainly to do with the voltage swing achieved...some only achieve just over two volts...whereas particularly older autopilots require a full TTL level 5volt swing to operate.
You dont say which laptop plotting software you are using...or did I miss that..?
Let me know the software you are using and I'll see if I can find a solution for you.
You can always use a PCMCIA to dual port serial converter card.
These are generally much better than USB units...will give you "proper" com ports
without many of the hassles of NMEA on USB.
These can be bought online for around 40 pounds or less.

Steve.
 
thanks for your help folks im getting more knowledgable on this lot by the minute

Ive got the prlofic usb/serial connecting Cmap on laptop with Magellan320 this works fine with the magellan cigar ligter power and serial cable.

the cmap set up allows me to talk to an autopilot. the question is more engineering than software. ie

ive 2 wires from the nmea on the autopilot (rayth 4000+ 2 yrs old) and 3 wires ( 2power and one data FROM THE CLIPPER REPEATER) do i have to split my magellan cable and connect these extra 5 wires and ifso which goes to what. or is there a dead clever DIY way which saves me on a multiplexer.
 
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