Hello Decodium Team, I’m an Elecraft KX3 owner and Decodium works great there. I recently got a K4D I’d like to request support for the Elecraft K4 series in Decodium. Elecraft provides a complete, documented IP‑based control API for the K4, including CAT commands, panadapter data, audio streaming, and both a COM port CAT interface as well as multi‑client TCP which includes CAT control and audio streaming in both directions. I can supply logs, command traces, and testing if needed. Many K4 operators are looking for a modern, integrated interface like Decodium, and adding K4 support would be a great enhancement for the community, and further support Decodium as the preferred FT2-8 digital software package. Here's some useful technical background I'm hoping that can help K4 support onto your schedule: 🔧 1. TCP/IP Control (K4 Native Network Protocol) The K4 is fundamentally a network‑native radio. Its entire control architecture is built around IP connectivity. When you connect over TCP/IP, you are using the full Elecraft K4 Network API, which includes: ✔ CAT over TCP (Command/Response) A TCP socket (default port 9200) provides: GET commands (query radio state) SET commands (change radio state) Auto‑Info broadcast (unsolicited state updates) Multi‑client support (multiple programs can connect simultaneously) This is far more capable than legacy serial CAT. ✔ Panadapter Streaming The K4 streams spectrum data over IP: FFT bins dB values Waterfall data Multiple panadapters simultaneously This is how Win4K4Suite, K4 Remote, and QK4 display real‑time spectrum. ✔ Audio Streaming The K4 can stream: MAIN audio SUB audio IQ data (optional) This is how remote programs decode digital modes or play audio locally. ✔ Multi‑Client Architecture Unlike older radios, the K4 allows: CAT client Panadapter client Audio client K‑Pod client Logging software Digital‑mode software …all connected at the same time. ✔ Remote Operation Without a Local PC Because everything is IP‑based, you can operate the K4: directly from a laptop from a tablet from a remote PC from a K4/0 front panel from multiple software clients No local computer is required. 🔌 2. USB CAT (COM Port) via Elecraft USB Cable When you plug the K4 into a computer via USB, the radio exposes: ✔ A virtual COM port (CDC‑ACM device) This is a serial‑over‑USB interface that emulates a traditional RS‑232 CAT port. It supports: Kenwood‑style CAT commands Elecraft‑specific extended commands 38,400 baud One client only No panadapter streaming No audio streaming No multi‑client support This is the “legacy” control path. ✔ What USB CAT is good for WSJT‑X N1MM Logger+ fldigi Winlink Any software expecting a COM port Simple CAT control PTT Frequency/mode control ✔ What USB CAT cannot do No panadapter data No waterfall No audio No IQ No multi‑client operation No remote operation unless tunneled through NoMachine/TeamViewer/etc. ✔ Why USB CAT exists It provides backward compatibility for software that: cannot speak TCP/IP cannot parse Elecraft’s network protocol expects a COM port uses hamlib serial drivers