# PCIe 4-port RS232 Serial Adapter Card StarTech PEX4S953LP — 16950 UART, 256B FIFO, Low Profile

**URL:** https://aio.lv/en/product--startech-pex4s953lp--3450437
**Data updated:** 2026-03-11 11:43 (EET)
**Category:** I/O Adapters & Controllers
**Manufacturer:** StarTech
**Manufacturer code:** PEX4S953LP
**EAN:** 0065030887052
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 126.49 €
**Prices and availability valid until:** 2026-07-18 23:59
**Price without VAT (21%):** 104.54 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--startech-pex4s953lp--3450437

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 06.07.2026 | free |
| Pickup points | 09.07.2026 | 1.99 EUR |
| Courier delivery to door | 09.07.2026 | 4.99 EUR |

## Summary description

PCIe 4-port RS232 serial adapter card by StarTech (PEX4S953LP) provides four DB9 serial ports via a PCI Express host interface. Based on the Asix AX99100 chipset with 16950 UART and 256-byte FIFO, it supports baud rates up to 921.6 Kbit/s and PCIe 1.1 expansion standard. Low-profile form factor (75×63×18 mm), compatible with Windows and various Windows Server versions. CE/FCC certified, MTBF 214,358 h.

## Long description

The StarTech PEX4S953LP is a PCIe 4-port RS232 serial adapter card that adds four DB9 serial ports to a desktop or server via a PCI Express slot. It uses the Asix AX99100 chipset with an industry-standard 16950 UART and 256-byte FIFO buffers, and supports baud rates up to 921.6 Kbit/s. The card is PCI Express 1.1 compliant, supplied with low-profile and optional full-profile brackets for installation in different chassis, and is CE/FCC certified with an MTBF of 214,358 hours. Drivers are available for Windows and supported Windows Server versions; Linux compatibility is also indicated.
Advantages
The adapter provides four independent RS232 (DB9) ports on a single PCIe card, enabling high-speed serial communication up to 921.6 Kbit/s. Built on a 16950 UART with 256-byte FIFO per transmitter and receiver, it reduces CPU interrupts and improves data throughput for multiple simultaneous serial connections. The low-profile form factor and included full-profile bracket simplify installation in a range of systems. Compliance with PCIe 1.1 and CE/FCC certification ensure reliable interoperability and regulatory compliance.
Suitable for
Connecting legacy serial devices such as receipt printers, barcode scanners, and industrial controllers
Integrating point-of-sale terminals, PIN pads, and card readers that require RS232 interfaces
Managing serial communications for network equipment, modems, and laboratory instruments
Expanding serial port capacity in servers and workstations with limited onboard COM ports
Key specifications
Interface: PCI Express (PCIe) 1.1 host interface
Serial ports: 4 × RS232 DB9 connectors
Chipset: Asix AX99100
UART: Industry-standard 16950
FIFO: 256-byte FIFO per transmitter and receiver
Maximum baud rate: Up to 921.6 Kbit/s
Form factor: Low-profile card (includes full-profile bracket)
Power output: 5/12V on Pin 9 when external power is connected
Certifications: CE, FCC
MTBF: 214,358 hours
How to use
Power down the computer and insert the card into an available PCIe slot, choosing the low-profile or full-profile bracket as appropriate for your chassis. Secure the bracket, reconnect power, and boot the system. Install the appropriate drivers for your operating system (Windows, supported Windows Server versions, or Linux) following the vendor instructions. Connect serial devices to the DB9 ports and configure port settings (baud rate, data bits, parity, stop bits) in your OS or serial communication software to match the connected devices. If external power is required for pin 9 output, connect the external power source as specified by your device documentation.
Usage recommendations
Use shielded serial cables to minimize interference and verify baud rate and handshake settings for each connected device. For stable multi-device communication, enable the card's FIFO buffering and match serial parameters to the peripheral's requirements; consult device manuals for recommended power connections if using the 5/12V output on pin 9.

## Specifications

### Operational conditions

| Feature | Value |
|---|---|
| Operating relative humidity (H-H) | 5 - 85 |
| Storage temperature (T-T) | -20 - 100 |
| Operating temperature (T-T) | -10 - 80 |

### Technical details

| Feature | Value |
|---|---|
| Compliance certificates | RoHS |

### Ports & interfaces

| Feature | Value |
|---|---|
| Host interface | PCIe |
| Output interface | Serial |
| Expansion card standard | PCIe 1.1 |

### Other features

| Feature | Value |
|---|---|
| Quantity | 1 |

### Weight & dimensions

| Feature | Value |
|---|---|
| Weight | 0.264 kg |
| Package weight | 370 g |
| Height | 18 mm |
| Width | 75 mm |
| Depth | 63 mm |

### System requirements

| Feature | Value |
|---|---|
| Windows operating systems supported | Windows 10 Pro x64, Windows 10 Pro, Windows 10 IOT Core, Windows 10 Home x64, Windows 10 x64, Windows 10 Education x64, Windows 10 Home, Windows 10 Enterprise x64, Windows 10 Enterprise, Windows 10, Windows 10 Education, Windows 8.1, Windows 7, Windows 7 Enterprise, Windows 7 Enterprise x64, Windows 7 Home Basic, Windows 7 Home Basic x64, Windows 7 Home Premium, Windows 7 Home Premium x64, Windows 7 Professional, Windows 7 Professional x64, Windows 7 Starter, Windows 7 Starter x64, Windows 7 Ultimate, Windows 7 x64, Windows 8.1 x64, Windows 8.1 Pro x64, Windows 8.1 Pro, Windows 8.1 Enterprise x64, Windows 8.1 Enterprise, Windows 8 Pro x64, Windows 8 Pro, Windows 8 Enterprise x64, Windows 8 Enterprise, Windows 8, Windows 7 Ultimate x64 |
| Linux operating systems supported | Y |
| Server operating systems supported | Windows Server 2016, Windows Server 2012 R2, Windows Server 2012, Windows Server 2008 R2, Windows Server 2003 |

### Design

| Feature | Value |
|---|---|
| Internal | Yes |
| Product colour | Green |

### Performance

| Feature | Value |
|---|---|
| Certification | CE, FCC |
| Mean time between failures (MTBF) | 214358 h |
| Chipset | Asix AX99100 |

### Logistics data

| Feature | Value |
|---|---|
| Master (outer) case height | 235 mm |
| Master (outer) case width | 480 mm |
| Master (outer) case length | 350 mm |
| Products per master (outer) case | 16 pc(s) |
| Harmonized System (HS) code | 84733020 |

### Features

| Feature | Value |
|---|---|
| Baud rate | 921.6 Kbit/s |
| Data bits | 6, 5, 7, 8, 9 |
| Stop bits | 1, 1.5, 2 |
| Parity bit | Even, Mark, N, Odd, Space |
| Flow Control type | XON/XOFF, N, RTS/CTS |
| FIFO (First In, First Out) | 256 |

### Packaging data

| Feature | Value |
|---|---|
| Cables included | Serial |
| Package depth | 149 mm |
| Package height | 51 mm |
| Package width | 213 mm |
| Quick installation guide | Yes |
| Mounting brackets included | Yes |

## FAQ

### How much does the StarTech PEX4S953LP PCIe 4-port RS232 Serial Card cost, and is it available for purchase?

The price is 126.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 68 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 06.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay, Installment. All transactions are 100% secure and encrypted.

### Can StarTech PEX4S953LP PCIe 4-port RS232 Serial Card be purchased with a lease?

Yes, the purchase is available both on credit and with an interest-free installment plan. Learn more about installments and credit options: https://aio.lv/en/payment#b3

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All StarTech products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized StarTech service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

### How can I tell if this product suits my needs?

When making a choice, we recommend paying attention to the key features: host interface, weight, internal, output interface, product colour, compatibility with your devices or usage conditions, material quality, functionality, and warranty terms. These characteristics will help you determine how well the model meets your needs.

### Where can I download the instructions for StarTech PEX4S953LP PCIe 4-port RS232 Serial Card?

You can download the instructions in PDF format from the “Instructions” section on the product description page. The file contains complete information about installation, setup, and usage.

## Image

https://aio.lv/img/cache/product/3450437/64216307_large.webp