> For the complete documentation index, see [llms.txt](https://emotiv.gitbook.io/extender-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://emotiv.gitbook.io/extender-manual/extender-quick-start/updating_the_real-time_clock.md).

# Syncing real-time clock

Extender has a real-time clock which it uses to timestamp a recording. Before you get started recording files it is a good idea to update the RTC by syncing it to your computer using our service application, EMOTIV App. If you carry out a hardware reset or the device is left unused for a while we recommend syncing the clock again. For more information about using Cortex, visit the Cortex user manual [here](https://emotiv.gitbooks.io/cortex-manual/).

To sync your real-time clock:

1. [Install](https://www.emotiv.com/get-started/) and open EMOTIV App on your PC or laptop
2. Connect your Extender via USB to your computer. Please ensure it is powered on (green light on) and the microSD card is removed.
3. Click on the ![](https://lh4.googleusercontent.com/AGoW4m0r8llxdcJSIcT5LITkJ_3ZNw9eVdsiwT7SLABPy8coj9L1cAVUvwMNsblArTVc2Xj0gMTguWyu-2dk2BuiR5VksDW__r0j2Lyf4TcYDRDC2ZgXCc4jNDR1kC9gdvpAeBdX)  icon on the connected device panel on Cortex to reveal options list
4. Select “Sync clock” from the drop down menu
5. Wait for the sync to finish and success message to appear at the bottom of the app screen
6. Hold down the power button for 3s until the green light turns off.
7. Press the button again to turn back on your Extender and confirm that the clock is up to date.

  \
\&#xNAN;*Note: if you do not see time clock information, please update Extender firmware.*

![](/files/-LIeRw-Nn4xpx8vwJ4X5)


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