STARTECH PEX2S953LP 2-Port RS232 PCIe Serial Expansion Card

Two RS232 ports on PCIe x1

This card adds two DB-9 serial connections through a single PCI Express x1 slot using the Asix AX99100 controller with 16950 UART. It targets administrators maintaining legacy serial equipment such as industrial controllers, console servers or modem banks. The 921.4Kbps maximum rate supports most RS232 workloads without saturating the bus.

Low-profile bracket included

A half-height bracket is supplied alongside the standard full-profile bracket so the card fits 1U servers and slim workstations as well as full-size towers. An LP4 power connector on the board draws auxiliary current for the UART logic, leaving the PCIe slot to handle only signalling. No external power brick or cable routing is required beyond the internal drive-power lead.

256-byte FIFO per port

Each transmitter and receiver offers a 128-byte depth FIFO, giving 256 bytes total buffer per port to absorb bursty traffic at 921.4Kbps. The driver stack supports Windows Server 2003 through 2016 and Linux kernels 2.4.x to 2.6.x LTS only; newer kernels or desktop Windows releases are not covered. Builds needing more than two ports or higher throughput will require additional cards.