# Can I use the XBEE module in a 4.2V RS-232 serial communication?

**URL:** <https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922>\
**Category:** XBee - 802.15.4\
**Tags:** voltage-levels, rs232, xbee\
**Created:** [May 7, 2014, 9:32am UTC](https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922 "2014-05-07T09:32:20Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![moussaprince](https://avatars.discourse-cdn.com/v4/letter/m/ed655f/32.png) [@moussaprince](https://forums.digi.com/u/moussaprince)\
**Post date:** [May 7, 2014, 9:32am UTC](https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922/1 "2014-05-07T09:32:20Z")

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I have two calculators (algebra fx 2.0 plus) which I made communicate by a serial connection RS-232, with the cable RX-TX-GND. I wanted to use a wireless connection, so I bought two XBEE modules :), set the same speed on the calculators and on the XBEE… However, I know that the serial communication of the XBEE is basically 0/3.3V, while my calculator operates with 0/4.2V … I think the calculator can read the 3.3V as a high logical level (one), but can I take the risk of overpowering the XBEE RX (not the external power) with 4.2V?

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**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:** [May 7, 2014, 10:25am UTC](https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922/2 "2014-05-07T10:25:09Z")

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No you can’t connect the 3V XBee to the 4V? Device. You would need to use a level shifter between the two.

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<div class="post-metadata">

**Author:** ![moussaprince](https://avatars.discourse-cdn.com/v4/letter/m/ed655f/32.png) [@moussaprince](https://forums.digi.com/u/moussaprince)\
**Post date:** [May 7, 2014, 10:31am UTC](https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922/3 "2014-05-07T10:31:51Z")

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You mean a voltage divider like that:

calculator TX 4,2 V–\> voltage divider –\> xbee 3,3 V?

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<div class="post-metadata">

**Author:** ![moussaprince](https://avatars.discourse-cdn.com/v4/letter/m/ed655f/32.png) [@moussaprince](https://forums.digi.com/u/moussaprince)\
**Post date:** [May 7, 2014, 10:40am UTC](https://forums.digi.com/t/can-i-use-the-xbee-module-in-a-4-2v-rs-232-serial-communication/12922/4 "2014-05-07T10:40:58Z")

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By the way I am powering XBEE with 3.3V, and the RX pin with 4.2V…