M.2 (Key M/B) to Dual RS232 Serial Port Adapter Card – 2-Port COM DB9 Expansion Card, PCIe 2.0 Gen1 x1 Interface, Industrial-Grade Converter Compatible with Terminal & Embedded Systems

AoQhir M.2 (Key M/B) to Dual RS232 Serial Port Adapter Card – 2-Port COM DB9 Expansion Card, PCIe 2.0 Gen1 x1 Interface, Industrial-Grade Converter Compatible with POS, Modem📖Product DescriptionThis M.2 to Dual RS232 Serial Port Adapter Card converts your motherboard’s M.2 slot (Key M or Key B) into two standard DB9 RS232 serial ports, allowing you to connect and communicate with multiple serial devices simultaneously.Built on PCIe 2.0 Gen1 x1 interface, it provides full-duplex bidirectional communication at up to 921,600 bps baud rate, making it ideal for industrial automation, data acquisition, and embedded system integration.The adapter supports 16550-compatible UART registers, with 256-byte TX/RX FIFOs and two independent UART channels for reliable high-speed data transmission. It’s designed for connecting terminals, modems, barcode scanners, cash registers, ISDN adapters, serial printers, and other RS232-based devices.Technical SpecificationsInterface Type: M.2 (Key M or Key B), PCIe 2.0 Gen1 x1Number of Ports: 2 × RS232 (DB9 male connectors)Baud Rate: 300 bps – 921,600 bpsUART Type: 16550 compatible with 256-byte TX/RX FIFOsData Bits: 4, 5, 6, 7, 8Stop Bits: 1, 1.5, 2Parity: None, Even, Odd, Mark, SpaceFlow Control: None, Hardware (Compatible with RTS/CTS), Software (Compatible with Xon/Xoff)RS232 Signals: DCD, RXD, TXD, DTR, GND, DSR, RTS, CTS, RIOperating Temperature: -40°C to +85°C (-40°F to +185°F)Storage Temperature: -65°C to +150°C (-85°F to +302°F)🧩Application ScenariosIndustrial automation and control systemsPOS machines and cash register systemsBarcode scanners, printers, and modemsEmbedded computing and Mini-ITX platformsServer and gateway serial communication

• Dual RS232 Ports Expansion – Converts M.2 (Key M/B) slot to two standard DB9 serial COM ports for connecting multiple RS232 devices.
• PCIe 2.0 Gen1 x1 Interface – Compliant with PCI Express 2.0; supports bidirectional 2.5 Gbps data link per direction for stable and fast communication.
• High-Speed UART Performance – 16550-compatible UART with 256-byte FIFO, baud rates up to 921,600 bps, and independent dual-channel design.
• Industrial-Grade Reliability – Operating temperature from -40°C to +85°C (-40°F to +185°F); supports hardware and software flow control with multiple parity options.
• Broad OS Compatibility – Comaptible with Windows XP–10, Windows Server 2003–2019, and Linux 2.6.27 or newer; plug-and-play support for embedded and POS systems.