1. STRONG COMPATIBILITY: Connect sound codec, CAT control, and switch to a computer via a single USB connector. Compatible with Windows, macOS, and iOS. No drivers needed. 2. FULL FUNCTIONALITY: Works with FT8, FT4, JS8Call, SSTV, APRS, VaraHF, VaraFM, and Soundmodem. Allows full CAT control in compatible transceivers and adjustments for HT and basic mobile radios. 3. HIGH RELIABILITY: Prefabricated transceiver cables are available for popular models, providing a professional and user-friendly experience. 4. INTEGRATED INTERFACE: Combines sound card and serial port into one. Supports TTL/232 levels, USB serial control, and flexible connection to different devices with dual 3.5mm 4-pin jacks. 5. VERSATILE SOUND AND SERIAL PORTS: Defines sound input and output, PTT control (USB serial control, not sound-based), and serial port input and output (default TTL, switched to 232). Item Type: Integrated Digital Modes Interface Power Supply: USB Powered Interface: 1 x Sound, 1 x Serial Color: As Shown Material: Plastic Package Contents: 1 x Extension Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to vary slightly from the real thing. The measurement allowed error is +/- 1-3 cm.