Dave wrote:
I'm setting up a simple navigation system consisting of my Garmin GPS
and an old laptop running SeaClearII. Presently my GPS is tied into
the radio so that if I have to press the red button the broadcast
will include my position. I'd like to maintain that arrangement.

When I hook into the laptop it will be via a plug-in connection on
the GPS led to the serial port. As a result there will be no exposed
data in and data out wires to lead to the radio. I suspect there's
some easy way to solve this problem, but don't know what it is off
the top of my head. How have others done it?

"Presently my GPS is tied into the radio"

This is not enough info for anyone to provide you wuth help. What Garmin
GPS? What "radio"?

Do you mean a handheld Garmin with 2 wires from data-out and ground leading
to a GMDSS VHF radio? Or possibly a GPS plotter with chart display and a six
or seven-wire lead to the power source/data source? "Radio" is a term that
could mean anything from a crystal set to the very latest GMDSS or even a
car radio/CD player.

More info would enable us to help.

Dennis.