Originally Posted by geekmaster
Something odd about the kindle touch (and k4nt). It seems that the third pin that we have been calling "GND" (ground) does not make a good ground. The kindle serial i/o seems to work better when another ground is used, like a metal shield. Or, you can leave off the ground connection and keep the kindle USB connected to the same computer as the serial adapter, so it uses the USB cable ground as the serial ground.
Perhaps that third pin is CTS or DTR (hardware handshake)???
Might be. I think these serial ports wil do 400K+ speed serial lines.
Flow control is nice to have at those speeds.
Anything that is a "driven ground" (signal output in low state, this is CMOS) might act like a not-so-good ground point.
Do you have access to an O'Scope to check it with?
Maybe we should get someone with a lot of "Google Credits" to look up how to use the PC Audio Mic-In (or Line-in, in this case) jack as a quick-and-dirty O'Scope.