StarTech.com 4-port PCI Express RS232 Serial Adapter Card – PCIe RS232 Serial Host Controller Card – PCIe to Serial DB9 – 16950 UART – Low Profile Expansion Card – Windows, macOS, Linux (PEX4S953LP)

This PCI Express RS232 serial adapter card lets you add four RS232 (DB9) serial ports to your computer through a PCI Express (PCIe) slot. The 4 port PCIe serial card enables you to interact with serial devices, such as card readers, printers, PIN pads, and modems, at speeds of up to 921. 6Kbps.
Maximum Compatibility
With broad OS support, including for Windows and Linux, this PCI E serial card is easy to integrate into mixed environments. The card comes pre-configured with low-profile brackets, and includes optional full-profile brackets, so installation is easy regardless of the case form factor. This card is a direct replacement for PEX4S952LP.
Experience Optimal Technology
This PCIe to serial adapter supports a max baud rate of up-to 921. 6Kbps, 9, 8, 7, 6, 5 data bits (one per port), and provides 5/12V power output on Pin 9 when external power is connected. It also supports 256-byte depth FIFO cache per transmitter and receiver, is compatible with industry standard 16950 UART, and is PCI Express 1. 1 compliant. The PCIe expansion slot features an Asix AX99100 chipset.
Reliability
PEX4S953LP is backed by a StarTech lifetime and free lifetime technical support.