# fdMonitor only works sporadically

**URL:** <https://forum.legato.io/t/fdmonitor-only-works-sporadically/6438>\
**Category:** Legato Application Framework\
**Created:** [February 22, 2023, 12:44pm UTC](https://forum.legato.io/t/fdmonitor-only-works-sporadically/6438 "2023-02-22T12:44:44Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.legato.io/jyijyi/32/822_2.png) [@jyijyi](https://forum.legato.io/u/jyijyi)\
**Post date:** [February 22, 2023, 2:05pm UTC](https://forum.legato.io/t/fdmonitor-only-works-sporadically/6438/2 "2023-02-22T14:05:30Z")

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if you want to isolate whether this is related to legato API, you can simply use open(),read(),write() generic API to control the UART:

> [@UART flow control with WP7608](https://forum.legato.io/t/uart-flow-control-with-wp7608/4597/51):
>
> Maybe you can run my sample application attached here. It will change the status of CTS every three seconds. It is working on my WP7608 FW R12.[UART\_Test1.rar](https://forum.legato.io/uploads/short-url/4AvEFawZzHvfUcT1URfB8G3VPHu.rar) (99.5 KB)

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