> For the complete documentation index, see [llms.txt](https://emotiv.gitbook.io/emotivpro-v3/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/emotivpro-v3/event-markers/serial-port-markers.md).

# Serial port markers

EmotivPRO can receive automatic markers via serial ports (TTL and virtual), so that you can perform event-related experiments with high temporal precision.

To configure serial port markers using a real or virtual COM port:

1. Click on **Settings** which can be found at the top right-hand side of EmotivPRO.
2. Select **Serial port marking** from the menu on the left-hand side of the screen.
3. Select the configurations you need from each menu: COM port (real or virtual), bits per second (BAU), data bits, parity, stop bits, and flow control that are compatible with your sending device
4. Click on **Start** to save the configurations. 
5. Click on the back arrow at the top left-hand corner of the screen to go back to the Recording screen. 

![](https://lh6.googleusercontent.com/5V5UgDDiO6YdOuQfjVn6WOvOak9D-RT4dFrO0PWPky1d6kxrqx6d-HN-7HeRQyC7VfBJh1bdsy9mf2TJgBm4PRPQqk5Bq8VDQBVOg2e17LYJ6U71oTQASi5KZIidHjw7vgx_zjA8=s0)

You will see a vertical pink line in the data stream in Raw EEG, Performance Metrics and Motion Sensors views when a marker has been added successfully and will be able to view the markers in the recording timeline and exported data file.<br>