* On PiKVM V3 or V4, you have a built-in USB-UART adapter in your device. Just disconnect the OTG cable and place the USB-C end into `IOIOI` port on V4 (or `CON` port on V3). Place the USB-A end into the port you want serial to be accessed, typically done on the host. If you have a Windows host, you may need to install this [driver](https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers), other OS's may not need one.
* On DIY PiKVM V1 or V2, you'll need to get the right TTY to USB cable, we recommend the [RPi Debug Probe](https://www.pishop.us/product/raspberry-pi-debug-probe/) and follow existing RPi TTY serial setups.
4. Select the COM port in Putty (you can verify this looking in Device Manager), then select 115200, or use `screen /dev/ttyUSB0 115200` for other OS's
Most of the PiKVM settings are done through configuration files. All configuration changes must be made from under the `root` user (i.e. the administrator).
The PiKVM memory card is mounted in read-only mode. It protects the filesystem from damage in case of sudden power outage. To edit any files and make changes, it is necessary to remount the file system to the read-write mode.
* To enable write-mode, run command `rw` (under `root`).
* To disable it, run command `ro`.
* If you receive the message "Device is busy", perform `reboot`.
In this handbook, you will often find instructions for editing configuration files. The simplest and most beginner-friendly text editor is `nano`, but you can also use `vim`.
Most of the PiKVM configuration files are located in the `/etc/kvmd` directory.
The `/etc/kvmd/main.yaml` file defines the platform config and **you should never edit it**. To redefine system parameters use the file `/etc/kvmd/override.yaml`. All other files that are also not recommended for editing have read-only permissions.
In the `/etc/kvmd/meta.yaml` file you can specify some information regarding the host that this PiKVM manages.
!!! tip
A complete list of all parameters can be viewed using the `kvmd -m` command.
Files with the suffix `*.yaml` uses the [YAML syntax](https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html)
and describes a parameter tree with key-value pairs of different types.
To define the parameters within one section, an indent of 4 spaces is used.
Comments starts with the `#` symbol.
!!! warning "Only 4 spaces should be used for indentation"
Be careful when editing YAML and follow this rule.
Invalid indentation or tabs instead of spaces will cause an error when starting the services.
??? example "Sections under the same keys should be merged"