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May 11, 2006
about 3 years ago
Nothing against this product, it is what it says it is. I'm just commenting in case there's anyone out there who (like me) found out after the fact that 1/2" copper pipe is actually not 1/2" in diameter... (more like 5/8") :)
about 13 years ago
The I and O on the TX and RX pins refers to those pins, specifically. The RX-I pin, the one on the four-pin header, is an input, and this is connected to pin 2 (RX) on the DE-9 connector. The TX-O pin, the one on the four-pin header, is an output, and this is connected to pin 3 (TX) on the DE-9.
This makes your microcontroller a DCE (modem), as opposed to a DTE (terminal), and as such, you should connect this to a computer (which is a DTE) using a straight-through DE-9 cable, not a null-modem cable.
With regard to level shifting, this board does not have a MAX232 or equivalent, so it does not comply with the classical RS232 spec (0 = Space = +12V, 1 = Mark = -12V). Instead, its input will accept RS232 voltages on the input and shift them (-12V [mark] -> VCC, +12V [space] -> GND). For its output, it merely inverts the signal (VCC->GND, GND->VCC) so you must be using a newer UART that will tolerate this.
I believe this is accurate - if it's not, feel free to correct me.
(Edited, accidentally referred to the TX-O pin as the TX-I pin.)
No public wish lists :(