Ok I've faithfully read all the posts regarding the empeg serial port and here's the understanding I got:
In order to connect a GPS, in this case an Oncore unit, I need to make a custom cable with no pins connected except 2,3 and 5 and 2/3 are crossed. So I took a perfectly good serial cable cut it, found the right colored wires by using a multimeter and connected them. I'm still not able to get GPSApp to see my GPS unit, it just says "Waiting for Data from GPS receiver"...
And yes I've tested this GPS unit fine under these circumstances:
My GPS unit works fine on my computer indoor, works fine on the empeg indoors
AND
it works fine on the empeg in the car using the serial port on the back (I connected the serial cable through the sled).

What other options do I have her? I guess I could recheck my serial cable again but I'm pretty sure I connected it right. Do I just need to pull the stupid sled out and bang away at this indoors? Any ideas?

IIRC the backside serial port and and the sled serial port aren't the same (DTE/DCE), so perhaps try uncrossing the two crossed lines?

/Michael

I've tried this.. let me explain a little further. The cable I used to connect to the backside is a straight-through one and this works. The cable I modified is a male-to-male one and I've tried uncrossing and crossing the lines. Weird thing is when I do not uncross the lines for this modified cable I hear a slight pulse through the speakers, once per second which goes away if I turn off the GPS unit.
Which makes me think the GPS is definetly working since that sound is the NMEA pulse, but something weird is going on preventing the signal from getting to the empeg.

Weren't some units shipped without a ground wire in the car serial connector? This would stop the serial link from working.

Just a thought....

Any idea how to test to see if I have a working ground? Could I just ground the serial cable ground to a known working ground, like the ground from my GPS power cable (which comes from the cig. lighter)? Or will that cause bad things?

Ok figured it out... my custom serial cable was obviously wired wrong I had four little stripped wires going to cross TxD and RxD but I ended up shorting them because I wasn't careful enough. To make a long story it works now. Of course it wouldn't have worked until I made myself look like an idiot publically, like I just did, that's just Murphy's Law.

Lovely stuff, enjoy your GPS!