StarTech PEX4S232485 – 4-Port PCI Express Serial Card (Multi-Protocol)

Overview :

The PEX4S232485 is a high-performance, multi-protocol PCI Express serial interface card designed for industrial automation, POS systems, and scientific instrumentation. It addresses the need for versatile legacy connectivity by providing four serial ports that can be individually configured for RS-232, RS-422, or RS-485 communication. This flexibility allows IT professionals to support a diverse range of peripherals—from barcode scanners and receipt printers to industrial PLC and CNC machinery—using a single expansion slot.

Technically, the card utilizes a native PCIe single-chip design (1x lane) to ensure maximum compatibility and performance with modern motherboards. Each of the four ports features a 256-byte FIFO buffer to reduce CPU overhead and ensure smooth data transmission at baud rates up to 921.6Kbps. Configuration is handled via onboard DIP switches, allowing for precise control over 2-wire or 4-wire RS-485 modes and termination settings.

The hardware is built for professional reliability, featuring a break-out cable design (DB44 to 4x DB9) that minimizes the physical footprint on the back of the PC. It includes both full-profile and low-profile brackets, making it suitable for standard desktop towers or small form factor (SFF) industrial PCs. The card is OS independent, with broad driver support for Windows, Windows Server, and Linux.

Key Features :

Individually configurable ports support RS-232, RS-422, and RS-485 protocols.

High-speed data transfer rates up to 921.6Kbps for rapid device response.

Native single-chip PCIe design provides enhanced reliability and speed.

Includes both standard and low-profile brackets for versatile installation.

Onboard DIP switches enable easy hardware-level protocol selection.