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Green circuit board with four silver DB9 ports and a low-profile metal bracket

STARTECH

STARTECH PEX4S953LP 4-Port PCI Express RS232 Serial Expansion Card

SKU CH-MRM2-W0Q9B MPN PEX4S953LP

Adds four RS232 DB9 serial ports via a PCI Express slot with 256-byte FIFO and 921.6 Kbps maximum baud rate

  • TypePCI Express to Serial Port Card
  • External Ports4 - DB-9 (9 pin, D-Sub) Male
  • Internal Ports1 - LP4 (4 pin; Large Drive Power) Male Input
  • Operating Systems SupportedWindows 7, 8, 8.1, 10 Windows Server 2003, 2008 R2, 2012, 20
  • SpecificationsHARDWARE Bus Type: PCI Express Card Type: Standard Profile (
  • FeaturesPCI Express 1.1 compliant replacement to the PEX4S952LP Seri
  • Add four serial ports via a single PCI Express slot
  • 6 Kbps max baud rate with 256-byte FIFO cache
  • Asix AX99100 chipset provides 16950 UART compatibility
  • Low-profile bracket pre-installed with full-profile bracket included
  • Supports Windows 7 through 10 and Linux 2.4.x to 2.6.x LTS

Four RS232 ports via PCI Express

This card adds four DB9 serial ports through a single PCIe slot. It targets technicians who connect legacy printers, modems or industrial equipment to modern systems. The Asix AX99100 chipset handles the translation with a 16950-compatible UART. Windows and Linux 2.4.x to 2.6.x LTS drivers are provided.

Low-profile bracket fitted, full-height included

The low-profile bracket ships installed for slim chassis, while a full-height bracket is supplied for standard cases. Ports are integrated on the board and break out through a DB9 cable. An LP4 power connector feeds the card, and the 256-byte FIFO buffers each channel at up to 921.6 Kbps.

Replaces the PEX4S952LP with PCIe 1.1 compliance

This model supersedes the older 952LP card while keeping the same four-port layout. The jump is worthwhile when a motherboard lacks native serial headers or when existing serial cards fail. Buyers who need more than four ports or USB-based serial conversion should look elsewhere.

Highlights

  • Add four serial ports via a single PCI Express slot
  • 6 Kbps max baud rate with 256-byte FIFO cache
  • Asix AX99100 chipset provides 16950 UART compatibility
  • Low-profile bracket pre-installed with full-profile bracket included
  • Supports Windows 7 through 10 and Linux 2.4.x to 2.6.x LTS

Specifications

BrandStarTech.com
ModelSerial Adapter Card
TypePCI Express to Serial Port Card
External Ports4 - DB-9 (9 pin, D-Sub) Male
Internal Ports1 - LP4 (4 pin; Large Drive Power) Male Input
Operating Systems SupportedWindows 7, 8, 8.1, 10
Windows Server 2003, 2008 R2, 2012, 2012 R2, 2016
Linux 2.4.x to 2.6.x LTS Versions only
SpecificationsHARDWARE
Bus Type: PCI Express
Card Type: Standard Profile (LP bracket incl.)
Chipset ID: Asix AX99100
Interface: Serial
Port Style: Integrated on Card
Ports: 4
PERFORMANCE
Data Bits: 5, 6, 7, 8, 9
FIFO: 256 Bytes
Flow Control: None, Xon/Xoff, RTS/CTS
Max Baud Rate: 921.6 Kbps
Parity: None, Odd, Even, Space, Mark
Serial Protocol: RS-232
Stop Bits: 1, 1.5, 2
FeaturesPCI Express 1.1 compliant replacement to the PEX4S952LP Serial Card, ensuring wide compatibility
Add RS232 DB9 capabilities without purchasing a new server or computer
Low profile bracket comes pre-installed, a full profile is also included for case compatibility
Supports 256-byte depth FIFO cache per transmitter and receiver
High-speed data transfer rates of up to 921.6Kbps with the ASIX AX99100 Chipset
Dimensions3" x 2.5" x 0.7"
Weight0.58 lb.
Package Contents1 - 4-Port Low Profile Serial Card
1 - 4-Port DB9 Break-out Cable
1 - Full Profile Bracket
1 - Quick-Start Guide
Shipping weight0.37 kg
Package size213 × 150 × 51 mm

Questions about this item

What PCI Express version does the PEX4S953LP use, and what speed limit does that place on each serial port?

The card is PCI Express 1.1 compliant and each RS232 port reaches a maximum of 921.6 Kbps with a 256-byte FIFO buffer.

Which brackets and cables are required to fit the card into a standard or low-profile chassis?

A low-profile bracket is pre-installed and a full-profile bracket is included; the DB9 break-out cable connects to the on-board header to provide four external ports.

How is the PEX4S953LP installed, and what power connection is often missed?

Insert the card into a PCIe slot, secure the chosen bracket, then plug the LP4 power connector from the PSU into the card's 4-pin input so the UART receives power.

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