Flow Control on XBee Series 1

Hi all,

I have a pair of XBee Series 1s sending serial data, everything works perfectly.

I’ve got one mounted on an Arduino with the XBee shield, the other is connected to my PC through the Sparkfun XBee Explorer USB (http://www.sparkfun.com/products/8687 ). But essentially the PC sees the XBee on the COM3 serial port.

The Arduino is doing some measurements and sending the data to the PC. Again, this all works perfectly.

Now here’s the strange part - the second XBee only transmits the data it receives over wireless when the COM port is open. (I can see the RX LED flash on the Sparkfun board).

This is easily replicated in X-CTU - when I press the “Close COM port” button in the Terminal, the data stops flowing (RX stops flashing) in about a second.

Changing the assertion of DTR and RTS doesn’t do anything - so I’m wondering how else the XBee knows the port is open or closed?

If I set ATD6 to 1, then it responds to RTS flow control perfectly (i.e. it stops sending the received data instantly). But this is not what I want.

Ultimately, I want to move the XBee into its own dedicated circuit and for it to always send the received data regardless of whether anything is connected.

How can I accomplish this? AT settings or hardware solutions work for me.