I have a simple wireless project that requires two serial ports. One of them, critical to the function, will be tied to the UART on the XBee. The second, just for low data rate logging, I'd like to send over the DIO pins on the XBEE. I understand data rate might be low, but even 300 baud would be fine.
I have seen a number of people asking this question across the net and usually they are dissuaded for any number of reasons. Either noone answers or it is recommended that they find some other solution.
But we all know this should work.
I have attempted to configure two XBee's identically, where DIO2 is DI and DIO3 is DO (up or down, I have tried both.)
One modem, I plug in to an FTDI cable so that DIO2 and DIO3 are plugging to TX and RX respectively.
The other, I simply power and then jumper DIO2 and DIO3 so they, in essence, loop back.
Obviously, this doesn't work. I suspect that there needs to be a pull up or pull down resistor at some point, though I understand this may be handled internally by the XBee.
I have read a number of pages on using DIO on the XBEE (including http://www.ladyada.net/make/xbee/ref.html) but I have not accomplished this task on my own.
This seems like a useful solution that is perfectly simple to perform, but I lack the knowledge of the internals of the XBee to solve this as of now.
I think this would be a very useful hack for any number of reasons and I know I'm not the only person looking for the answer.