Ok,
Here's the deal. I just went out and bought a nifty new GPS receiver for my car. I wired it up to power and serial and everything seems to check out OK, except when the antenna is plugged into the serial port coming out of the docking sled. GPSapp just sits in the "Waiting ..." mode.
When I connect the antenna's serial cable directly to the back of the RIO's serial port and use external power and force DC mode, GPSapp detects serial output from the antenna instantly, and there is much rejoicing.
I installed a straight through gender bender between the female end of the antenna serial cable and the female end of the serial cable coming from the sled.
I read something in the FAQ about the sled having a crossed cable vs. a null modem and something about the ground missing on some sleds...
http://www.riocar.org/modules.php?op=modload&name=FAQ&file=index&myfaq=yes&id_cat=8&categories=Known+problems+and+troubleshooting+questions&faqent=74#74
What angle should I start troubleshooting from?
TIA,
lothar