Intermittent transmission in transparent mode with two S2B Xbees

Hi everyone,

I am trying to get a simple point-to-point network working with two XBee Pro S2B ZB modules. I have tried API mode but failed to get it working two way. I have decided to fall back to transparent mode.

I have set up the firmwares and the destination addresses on both and ensured they have the same PAN. I have one of the modules in a SparkFun XBee Explorer USB and one in a SparkFun XBee Explorer Regulated connected to an Arduino Mega.

The Arduino program sends a single character once a second. For the first few seconds the characters are received successfully, as viewed in the Terminal window of X-CTU. However, after that there is a long pause of five or so seconds before a burst is received, then a few more consistent one second transmissions, and then another burst. This just keep repeating in a random manner. The transmitter light is flashing as predicted every second. Is there any obvious reason why the transmission is so sporadic, at such a low data rate?

I have measured the current draw and both modules appear to be drawing 20-50mA. This doesn’t seem like it would brownout the Arduino (can supply 50mA) or the XBee Explorer USB (should be able to supply 500mA). My guess is that its a power issue?

Am I missing something? Thanks in advance to anyone who offers help.


How are you addressing the packets? ZigBee requires an address.

If you have correctly configured the DH/DL with the MAC of the other unit, then the 5 second lag would only occur when a new ‘route discover’ occurs.

However, if you have enabled broadcast mode, then I would expect many such 5-seconds lags as under ZigBee broadcast are very disruptive.

Thank you! I had it under broadcast mode. I thought I had set the DH/DL. I set the DH/DL to be equal to the serial number and it works!

I am using freescale code warrior to program. I am trying out the application transparent, and haven’t been able to make it work.

When you said change DH/DL, do you mean in the code? or the addressing on the radio itself using bypass on X-CTU?

I have been looking everywhere for help, but I can’t find any sources…