Data Collision b/w two end devices (XBee Series 2)

Hi

I am using three XBee Series 2. Coordinator is Znet 2.5 coord AT 1047 while two end devices are Znet 2.5 Router/End AT 1247. Both of my end devices are connected to Lilypad Arduino. The o/p from them looks like
1, time1, sensor1, sensor2, sensor3
2, time2, sensor1, sensor2, sensor3
Both these o/ps are in char format. I am able to establish the communication successfully and receiving the data from both end devices in the arduino serial monitor.
But every now and then there is a collision (sometimes too much). This collision looks something like this
1, tim2, time2, sensor1, sensor2, sensor3
e1, sensor1, sensor2, sensor3
That is, the data from one is collapsing into other.

Could you please help in fixing the problem?
My application is simple getting data from two devices and I was wondering if there is a simple way other then API mode (though I don’t understand how do it either).

Any help would be appreciated.
Thanks

Hi ZigBee protocol is equipped with CSMA-CA. It can be unabled by RN command in 802.15.4 protocol module.

In your case it seems like than either you are facing interference problem or range of communication problem. You need to check out that either RF communication is not affected by UV light rays or another RF interference. Also you need to check out about that either between two modules in the RF communication Fresnel zone is proper or not? More details about fresnel zone you can find out in Digi Knowledge based articles.