> For the complete documentation index, see [llms.txt](https://docs.ceruleansonar.com/c/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ceruleansonar.com/c/manifold-5l-and-manifold-5s-ethernet-switch/connection-information/serial.md).

# Serial

The Manifold 5S has two serial ports usable when the Brain option is installed. One of the ports (SERIAL 2) can optionally use CTS/RTS hardware handshaking.

<figure><img src="https://2631968956-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMOwwlJpMRiOJF7MSvf2%2Fuploads%2FZrYSo0I1xkuJ0EX6ZhKu%2Fimage.png?alt=media&amp;token=23f0d3d7-16bd-49a7-8973-7f429cfe380f" alt=""><figcaption></figcaption></figure>

Pinout of the Serial connectors follow the Cerulean Sonar serial connector standard. See image below. "TX" means data comes out of the switch. "RX" means data goes into the switch.

<figure><img src="https://2631968956-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMOwwlJpMRiOJF7MSvf2%2Fuploads%2FQKHTT2SQo6wSWhc7EKFk%2Fimage.png?alt=media&amp;token=7c4c7f49-e6dc-4a83-99bd-1850eb7f6697" alt=""><figcaption></figcaption></figure>

CTS/RTS can be optionally connected to SERIAL 2's 2-pin JST connectors. Pin 1 is CTS, Pin 2 is RTS.