Xbee UART data line voltage drops

Hi All,

I am using the Xbee 900 HP in API mode to transmit data wirelessly. Everything works however I am concerned as when i look at the RX and TX lines to the Xbee using my oscilloscope I notice there are voltage drops of about 1.5V after my transmit signal. this drop is not large enough to effect the functionality of my design however they are concerning with no explanation.

For images of the signal drops please refer to this link:

I would suggest looking at your voltage regulator and making sure you have the proper level shifter’s in place.