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Green circuit board with gold edge connector and sixteen DB9 ports along the rear bracket

STARTECH

STARTECH PEX16S550LP 16-port low-profile serial expansion card

SKU CH-3JXY-C74EX MPN PEX16S550LP

Adds sixteen RS-232 serial ports via one PCIe slot with 921.6 Kbps throughput

  • External connectors16 x DB-9 (9 pin, D-Sub) Male
  • Internal ports1 x SP4 (4 pin, Small Drive Power) Male
  • Supported operating systemsWindows 7, 8, 8.1, 10 Windows Server 2003, 2008 R2, 2012, 20
  • Product typePCI Express
  • DetailsCard Type: Low Profile (SP bracket incl.) Chipset ID: ASMedi
  • Key features16 DB9 RS232 ports from a single PCIe slot Enables high-spee
  • Adds 16 serial ports through one PCIe slot using 16 DB9 connectors
  • Reaches 921.6 Kbps per port for fast RS232 communication
  • Fits low-profile and full-profile systems with included SP bracket
  • Works with Windows 7 through 10 plus Server 2003 to 2016 and Linux 2.6x to 4.2x LTS
  • Provides +/-15kV ESD protection and selectable 5V or 12V power on pin 9

16-port low-profile serial card

The StarTech PEX16S550LP adds sixteen DB-9 RS-232 ports through a single PCI Express slot. It targets industrial integrators, legacy equipment maintainers and server administrators who need many serial connections in a compact form factor. The low-profile design fits both slim and standard chassis without modification.

Passive cooling and minimal power draw

The card operates without a fan, relying on the host system airflow for thermal management. It draws auxiliary power through an internal SP4 connector with selectable 5 V or 12 V output on pin 9, keeping total consumption low. ESD protection rated at ±15 kV helps maintain signal integrity in electrically noisy environments.

Two breakout cables and a driver disc included

The package supplies two breakout cables that convert the on-board headers to the sixteen external DB-9 ports. A low-profile bracket is provided for slim chassis installations. The driver CD covers Windows 7 through 10, Windows Server 2003 through 2016 and Linux kernels 2.6 to 4.2 LTS, while a quick-start guide simplifies first-time setup.

How it compares

Measured against everything we stock in PCIe Expansion Cards, at today’s prices. Recalculated every night.

Price $320.99
Pricier than about 90% of the 891 comparable items (median $30.99).

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Specifications

Product
Brand nameStarTech.com
Model namePEX16S550LP
Product typePCI Express
Ports & slots
External connectors16 x DB-9 (9 pin, D-Sub) Male
Internal ports1 x SP4 (4 pin, Small Drive Power) Male
Size & build
Product dimensions0.9 in × 2.7 in × 6.6 in
Product weight0.16 lb (0.07 kg)
Shipping weight0.23 kg
Package size290 × 190 × 70 mm
Compatibility
Supported operating systemsWindows 7, 8, 8.1, 10
Windows Server 2003, 2008 R2, 2012, 2012 R2, 2016
Linux 2.6x to 4.2x LTS Versions only
In the box
In the box1 x serial card
1 x low-profile bracket
2 x breakout cables
1 x driver CD
1 x quick-start guide

Questions about this item

How do I install the PEX16S550LP in a low-profile chassis and which bracket do I use?

Fit the included low-profile bracket to the card, insert it into any PCIe x1, x2, x4, x8 or x16 slot, then connect the two breakout cables to the on-board headers and secure the DB9 panel brackets to the case. The step often missed is attaching the SP4 power cable to the card's 4-pin connector so the ports can supply 5 V or 12 V on pin 9.

What maintenance or replacement will the PEX16S550LP need over time?

The card has no moving parts or user-serviceable components. Driver updates for newer Windows or Linux kernels are the only ongoing requirement; if a port fails the whole card is replaced.

What limit appears first when all 16 ports run at 921.6 Kbps continuously?

The PCI Express 1.1 x1 link caps aggregate throughput, so sustained full-speed traffic on every port will hit the bus bandwidth ceiling before the individual UARTs reach their maximum rate.

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