Quote Originally Posted by Steve_88 View Post
Hi,

Can I drive an opto coupler or something similiar to isolate the GPS from the pic?

I've looked online a bit and searched the forums, but no hints so far.
Steve,

You are right, it's always a good practice to isolate the talker (gps) and listener (pic), esp. when you have multiple listeners connected in parallel to the talker.

In some cases the signal can drop pretty low and eventually some of the listeners will stop.

Also its eliminates any nasties when connecting devices that use RS232 and RS422 together.

In your case, use a standard opto isolator (6n136) with a 560 ohm resistor in series with TX line, and put a fast switching diode (1N4118 etc) across the input.

On the output side , use a 22K ohm resistor between Vcc and the out line, which connects to the pic.

Cheers
Squib