Quote Originally Posted by pedja089 View Post
I use 5 pin, so PIC Kit can be directly plugged in. And one of advantage of using 5 pin is that ground is in middle, so even if you reverse connector there is no reverse polarity.
I'd be concerned about potentially driving 13volts/Mclr onto the PGC/D pin if the 5pin header was reversed ;-(

I think the ultimate solution for a non-keyed connector would be using an 8pin socket, wiring the pins with opposing pairs of signals so a backwards fitted header would still be correct signals into the PIC.

e.g.

pins:
1 - GND
2 - PGC
3 - PGD
4 - VPP/Mclr
5 - VPP/Mclr
6 - PGD
7 - PGC
8 - GND

For me, i think i'll settle for a 4 pin KEYED header plug/socket. ;-)