Xbee controller lost first packets


I’m introducing into the Xbee world, and trying build a very simple network, with a controller and an endpoint.

All seems to be fine: open a console in Xctu or another terminal program, and when I write in controller’s window, all characters appears in endpoint’s window. But when I try in the other way, the first packets are lost.

I’ve tried to send a sequence of packets (by example, with ten characters in it), always loses the first X characters, in a range between 20 and 140 aprox.

The only way to avoid it is sending some characters from controller. Then, RSSI led is on in both devices, and endpoint can transmit without any loss.

I’ve switched the program in the two devices to discard some hardware faliure, but the result is the same.

Sorry for the complete-newbie question, but after hours of work, I’m totally stuck.


What version of XCTU are you using?

What XBee radio modules are you using, and which firmware?

What interface boards are the radio modules plugged into?

I don’t know what settings you’ve changed, but the most basic thing to do would be to reset the firmware on both radios and then reconfigure the addresses.

I’m pretty new to all this as well, but I have some ideas:

  • Is the controller sleeping? A firmware reset would fix that.
  • Maybe the controller Rx or endpoint Tx is weak. How far apart are the radios, and what antennas are they using?

Wow DystopianFerret, a lot of questions:

  • Xctu 6.3.1 (newest from the web, I think)

  • The radios, according the page of the seller, are XBee XB24-Z7WIT-004: http://tienda.bricogeek.com/modulos-radiofrecuencia/43-xbee-2mw-serie-25-con-antena.html

  • The radios are plugged into their respective Xbee explorer with usb interface. This one: http://tienda.bricogeek.com/modulos-radiofrecuencia/156-xbee-explorer-usb.html

  • I have programmed the controller with firmware version 20A7 and the other as router (as endpoint result is the same) with version 22A7, and only modified fields PAN id, destination address High and Low and node identifier. Other fields are the default values.

  • Signal is strong, now I’m just making experiments, thus both radios are at centimeters of distance.

  • And yes, I agree with you and suppose that controler is speeping, but I don’t know how check or change it.

Check the terminal view and see if the clear-to-send (CTS) indicator is solid or blinking. If it’s blinking on the transmitting device then something is wrong with it, like it might be sleeping. If it’s solid then the issue is probably with the receiver.

I would just restore the firmware to defaults. And double check the sleep mode settings.

I’m pretty sure that I’ve done before, but resetting the router to defaults works perfectly.

Thank you very much.

EDIT: After a minor change (given a name to the endpoint), it fails again. New reset, but now it’s not working!

Does your remote device have router or end device firmware on it?

Either way, try re-flashing the firmware from XCTU, not just restore-> write. That will ensure that you have a full clean install.

If it still fails after that, feel free to upload the profile and I can take a look.