# XBee pro 900HP development kit

**URL:** <https://forums.digi.com/t/xbee-pro-900hp-development-kit/13829>\
**Category:** XBee & XBee Gateway\
**Tags:** xbee-900hp\
**Created:** [October 30, 2014, 12:01am UTC](https://forums.digi.com/t/xbee-pro-900hp-development-kit/13829 "2014-10-30T00:01:31Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![naughty\_mark](https://avatars.discourse-cdn.com/v4/letter/n/848f3c/32.png) [@naughty\_mark](https://forums.digi.com/u/naughty_mark)\
**Post date:** [October 30, 2014, 12:01am UTC](https://forums.digi.com/t/xbee-pro-900hp-development-kit/13829/1 "2014-10-30T00:01:31Z")

</div>

Hello everyone,

I am a newbee to XBee Pro 900HP development kit. I can get communication between two modules by using X-CTU via USB connection to PCs, However, if I use serial port to connect development kit (PIN2-Dout, PIN3-DIN, PIN10-GND connected to my serial port on PC and power board via external power supply), the X-CTU can not communicate with module. I tested the signal on relative pins such as DOUT and DIN, the direction is correct but the voltage level looks odd. It can not reach 0 volt when it is low.  
So my question is, is that correct way I did to get communication with XBee via serial port? Did I do something silly so it not working?

Thanks for your help and time.

Kind Regards  
Mark

---

<div class="post-metadata">

**Author:** ![mvut](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.digi.com/mvut/32/31_2.png) [@mvut](https://forums.digi.com/u/mvut)\
**Post date:** [October 30, 2014, 8:21am UTC](https://forums.digi.com/t/xbee-pro-900hp-development-kit/13829/2 "2014-10-30T08:21:54Z")

</div>

The development board you are mounting the radio module on acts s a level shifter and a voltage regulator via the USB port. All other test points only provide direct access to the 3.3V CMOS level pins of the XBee module.