> For the complete documentation index, see [llms.txt](https://help.boomerang3.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.boomerang3.com/s2-radio-system-manual/s2-system-description/s2-node/rd001-serial-cable.md).

# RD001 serial cable

The RD001 serial cable is used to connect S2 node working as a PC node with a B2 server serial port. It is also used for programming S2 nodes, both to change their firmware and to set the radio network and node IDs as described in [S2 BLU Programmer](/s2-radio-system-manual/tools/s2-blu-programmer.md) and [S2 Init Node](/s2-radio-system-manual/tools/s2-init-node.md).

The cable is has an RJ11 plug on one side and DB9 female plug on the other.

<figure><img src="/files/hgcC6PGHTQCS3GNCQYjb" alt=""><figcaption></figcaption></figure>

The connections are shown on the schematic below.

<figure><img src="/files/bjfZhuRGMSuVG8qFOTNP" alt=""><figcaption></figcaption></figure>


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