{"product_id":"hl-340-usb-to-rs232-db9-serial-adapter-com-port-windows-linux","title":"HL-340 USB to RS232 Serial Adapter — DB9 9-Pin COM Port Converter for Windows \u0026 Linux","description":"\u003ch2\u003eHL-340 USB to RS232 Serial Adapter — DB9 9-Pin COM Port Converter\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eHL-340 USB to RS232 adapter\u003c\/strong\u003e adds a standard \u003cstrong\u003eDB9 RS232 serial COM port\u003c\/strong\u003e to any USB-equipped computer, enabling communication with legacy serial devices, industrial equipment, PLCs, GPS receivers, and microcontroller development boards that use RS232 signaling. Based on the HL-340 (CH340) USB-to-serial bridge IC, it is recognized as a standard COM port on Windows 7\/8\/10\/11 and Linux without requiring manual driver installation on most systems.\u003c\/p\u003e\n\n\u003ch2\u003eKey Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eChip\u003c\/td\u003e\n\u003ctd\u003eHL-340 \/ CH340 USB-to-serial bridge\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eInterface (PC side)\u003c\/td\u003e\n\u003ctd\u003eUSB-A (USB 1.1 \/ 2.0)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eInterface (device side)\u003c\/td\u003e\n\u003ctd\u003eDB9 male (RS232)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eRS232 Signal Levels\u003c\/td\u003e\n\u003ctd\u003e±12V (standard RS232)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eBaud Rates\u003c\/td\u003e\n\u003ctd\u003e300 bps – 921,600 bps\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eOS Support\u003c\/td\u003e\n\u003ctd\u003eWindows 7\/8\/10\/11, Linux (kernel driver), macOS (driver required)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eFlow Control\u003c\/td\u003e\n\u003ctd\u003eRTS\/CTS hardware flow control supported\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003ePower\u003c\/td\u003e\n\u003ctd\u003eUSB bus-powered (no external power required)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eCN\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eWhy Use the HL-340 Adapter?\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstant COM port\u003c\/strong\u003e — Plug into USB and Windows assigns a COM port number automatically; no PCI slot or motherboard RS232 header required\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTrue RS232 ±12V signaling\u003c\/strong\u003e — Onboard MAX232-equivalent level shifter generates proper RS232 voltage levels; compatible with all RS232 devices, not just TTL-level serial\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWide baud rate range\u003c\/strong\u003e — 300 bps to 921,600 bps covers everything from legacy 9600 bps modems to high-speed industrial serial protocols\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRTS\/CTS flow control\u003c\/strong\u003e — Hardware flow control support for devices that require it (modems, some PLCs)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBus-powered\u003c\/strong\u003e — No external power supply; draws power from the USB port\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTypical Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003ePLC programming and monitoring via RS232 serial port\u003c\/li\u003e\n  \u003cli\u003eCNC machine controller serial communication\u003c\/li\u003e\n  \u003cli\u003eGPS receiver NMEA data logging\u003c\/li\u003e\n  \u003cli\u003eIndustrial barcode scanner and label printer serial interface\u003c\/li\u003e\n  \u003cli\u003eLegacy modem and serial device connectivity\u003c\/li\u003e\n  \u003cli\u003eArduino serial monitor via RS232 (with TTL-to-RS232 adapter on Arduino side)\u003c\/li\u003e\n  \u003cli\u003eNetwork switch and router console port access\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eQ: Do I need to install a driver on Windows 10\/11?\u003c\/h3\u003e\n\u003cp\u003eWindows 10 and 11 include a built-in CH340 driver that installs automatically when the adapter is plugged in. If the COM port does not appear in Device Manager, download the latest CH340 driver from WCH’s official website (wch.cn) and install manually.\u003c\/p\u003e\n\n\u003ch3\u003eQ: Can I use this to program an Arduino?\u003c\/h3\u003e\n\u003cp\u003eThis adapter provides an RS232 DB9 port, not a TTL serial port. Arduino boards use TTL-level serial (0V\/5V or 0V\/3.3V). To connect this adapter to an Arduino’s TX\/RX pins, you need an additional RS232-to-TTL level converter. For direct Arduino programming, use a USB-to-TTL adapter (CH340G or CP2102 module) instead.\u003c\/p\u003e\n\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1× HL-340 USB to RS232 DB9 Serial Adapter\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Keszoox","offers":[{"title":"Default Title","offer_id":46991416000747,"sku":"\u003cnone\u003e","price":7.32,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/1005\/8731\/files\/hl340-usb-to-rs232-db9-adapter_2.webp?v=1761891436","url":"https:\/\/keszoox.com\/products\/hl-340-usb-to-rs232-db9-serial-adapter-com-port-windows-linux","provider":"Keszoox","version":"1.0","type":"link"}