# UART / RF latency with 802.15.4 module (XBee Pro)

**URL:** <https://forums.digi.com/t/uart-rf-latency-with-802-15-4-module-xbee-pro/20931>\
**Category:** XBee & XBee Gateway\
**Tags:** latency, tx, rx, 802-15-4\
**Created:** [November 25, 2019, 8:40am UTC](https://forums.digi.com/t/uart-rf-latency-with-802-15-4-module-xbee-pro/20931 "2019-11-25T08:40:40Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![francoiscadden](https://avatars.discourse-cdn.com/v4/letter/f/ed655f/32.png) [@francoiscadden](https://forums.digi.com/u/francoiscadden)\
**Post date:** [November 25, 2019, 8:40am UTC](https://forums.digi.com/t/uart-rf-latency-with-802-15-4-module-xbee-pro/20931/1 "2019-11-25T08:40:40Z")

</div>

Hello,  
We are facing a strange behavior using XBEE 3 module (802.15.4 mode with fw ver 2006).  
We send PPS synchronised messages from one XBEE module (@115200 bauds) and receive them with a measured latency about 40 ms between depending the case.  
We are communicating in broadcast mode.  
Could you tell me if such a latency is a “normal range” ?  
It make me think about a abnormal “buffer latency” inside the XBEE module.

Thanks for your feedback.

---

<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:** [November 25, 2019, 8:59am UTC](https://forums.digi.com/t/uart-rf-latency-with-802-15-4-module-xbee-pro/20931/2 "2019-11-25T08:59:12Z")

</div>

No, that looks to be normal.

[https://www.digi.com/support/knowledge-base/timing-comparison-for-data-transfer-by-product](https://www.digi.com/support/knowledge-base/timing-comparison-for-data-transfer-by-product)