Send CW with the input you have.
You do not need a dedicated key to begin. Use a keyboard, mouse, or touchscreen immediately, or connect one of the documented hardware paths when your browser supports it.
Input methods
The status shown below checks browser API availability only. A browser that can request device permission does not guarantee that an unlisted device or protocol is compatible.
Why there is no “generic COM port” option
A COM port is only a byte transport. CW hardware may send decoded text, raw key-down/key-up timestamps, WinKeyer frames, Morserino output, modem-control state, or a vendor-specific format. Those formats are not interchangeable.
To evaluate another serial device safely, provide its model, firmware version, documented protocol, baud rate, example receive-only frames, and whether timing is generated by the device or must be reconstructed from key events. The site will not send radio-control or transmit commands through a generic terminal.
Browser and permission notes
Software controls work in current graphical browsers. Serial and HID access require HTTPS, an explicit user action, and permission for the selected device. If a Connect button is unavailable, use the keyboard or on-screen controls and check this page again in a browser that exposes the required device API.
Firefox 151 and later expose Web Serial on desktop, while WebHID remains less widely available. Safari and iOS users should use software input unless the browser itself reports the relevant capability on this page.