Startech.com USB To Serial Adapter Cable ICUSB232V2 User Manual

Content

StarTech.com USB To Serial Adapter Cable ICUSB232V2 Manual

Introduction

The startech.com USB To Serial Adapter Cable ICUSB232V2 adds one RS-232 serial port to a computer through a standard USB Type-A connection. It is designed for connecting modern laptops and desktop computers to legacy equipment that uses a DB-9 serial interface, including industrial controllers, networking hardware, point-of-sale systems, laboratory instruments, GPS receivers, modems, and console ports.

This USB to RS232 adapter cable uses a Prolific PL2303-series chipset and supports communication speeds up to 921.6 Kbps. Its integrated 512-byte FIFO buffer helps manage data transfer between the USB host and serial equipment, while configurable parity, data-bit, stop-bit, and flow-control options support a wide range of serial applications.

The adapter is suitable for IT technicians, system administrators, industrial engineers, electronics hobbyists, and businesses maintaining legacy equipment. A 17-inch cable provides practical reach between a computer and a connected device without requiring a separate serial expansion card.

Unlike a simple USB-to-RS232 pin converter, the ICUSB232V2 provides an active interface that requires an appropriate driver and creates a virtual COM port in the operating system. This makes it possible to use terminal programs and device-management software that expect a conventional serial port. The adapter is intended for RS-232 equipment; it should not be connected directly to RS-422, RS-485, or TTL-level serial hardware unless a compatible converter is used.

Specifications and Key Features

Product type: USB to RS-232 DB-9 serial adapter cable
USB connector: USB Type-A male
Serial connector: DB-9 male
Number of ports: One serial port
USB standard: USB 1.1 and USB 2.0 compatible
Chipset: Prolific PL2303-series USB-to-serial controller
Maximum baud rate: 921.6 Kbps
FIFO buffer: 512 bytes
Data bits: 5, 6, 7, or 8
Stop bits: 1, 1.5, or 2
Parity: None, odd, even, mark, or space
Flow control: None, XON/XOFF, RTS/CTS, or DTR/DSR
Cable length: Approximately 17 inches or 43 cm
Serial protocol: RS-232
Operating temperature: 0°C to 60°C
Storage temperature: -20°C to 80°C

Performance depends on the connected device, selected serial settings, operating system, application, and cable quality. The maximum baud rate is a supported interface limit rather than a guarantee that every serial device can communicate at that speed.

How to Set Up the StarTech ICUSB232V2

Identify the serial equipment and confirm that it uses an RS-232 DB-9 connection. Check whether the equipment requires a straight-through or null-modem connection.
Download the correct Prolific PL2303 driver for the operating system from the product support page before connecting the adapter.
On Windows, extract the driver package, open the Windows folder, and run the Prolific driver installer. Follow the on-screen instructions.
On macOS, open the folder matching the installed operating-system version and run the supplied installer package.
Connect the USB Type-A plug to an available USB port. Avoid unpowered hubs when troubleshooting connectivity.
Open Device Manager on Windows and expand Ports (COM & LPT). Confirm that a Prolific USB-to-Serial Comm Port appears without a warning symbol.
Record the assigned COM-port number and select it in terminal, console, or equipment-management software.
Configure baud rate, data bits, parity, stop bits, and flow control to match the connected device. A common configuration is 9600 baud, 8 data bits, no parity, 1 stop bit, and no flow control, but the equipment manual takes priority.

Disconnect power from external equipment before attaching the serial connector when the equipment manufacturer recommends it. Do not force the DB-9 plug, connect incompatible voltage levels, or operate the cable where it may be exposed to moisture, excessive heat, or physical strain.

Troubleshooting the USB to RS232 Adapter

Adapter does not appear in the operating system

Install or reinstall the correct PL2303 driver, try another USB port, and restart the computer. On Windows, check Device Manager for a missing driver, warning symbol, or changed COM-port number.

“Prolific USB-to-Serial Comm Port” shows an error

Remove the device, uninstall the faulty driver entry, restart the computer, and install the driver package intended for the adapter and operating-system version. Avoid mixing older third-party PL2303 drivers with the manufacturer’s package.

Connected equipment does not respond

Verify the COM-port selection and match every serial parameter. Check whether the equipment requires a null-modem cable, hardware flow control, or software flow control. Confirm that the remote device is powered and configured for RS-232 rather than RS-485, RS-422, or TTL serial.

Garbage characters or intermittent data

Correct the baud rate, parity, data bits, and stop bits on both devices. Disable unnecessary flow control, reconnect the DB-9 plug, and test with a shorter or known-good serial cable.

Preventive measures and support

Document the working COM-port and terminal settings, avoid repeated cable bending, and disconnect equipment before changing wiring. For unresolved problems, use the product’s StarTech support resources, driver downloads, documentation, warranty service, and lifetime technical-support options. Have the model number, operating-system version, driver version, COM-port message, and connected equipment details available when requesting assistance.

Pros and Cons of the StarTech ICUSB232V2

Advantages

Convenient legacy connectivity: Adds an RS-232 DB-9 port to USB-equipped computers without installing an internal expansion card.
Broad serial configuration: Supports multiple data-bit, parity, stop-bit, and flow-control modes for industrial and professional equipment.
High stated transfer ceiling: Supports baud rates up to 921.6 Kbps, exceeding the needs of many console and control applications.
Integrated buffering: The 512-byte FIFO helps maintain orderly data transfer during normal serial communication.
Portable design: The compact 17-inch cable is useful for field service, bench testing, and temporary equipment configuration.

Limitations

USB Type-A dependency: Computers with only USB-C ports require a compatible USB-C hub or adapter.
Driver requirement: The adapter is not simply a passive cable; correct PL2303 software must be installed for the virtual COM port to function.
RS-232 only: It is not a direct replacement for RS-422, RS-485, or TTL serial adapters.
Connector limitation: The DB-9 male plug may require a gender changer, null-modem adapter, or additional cable for certain devices.
Best suited for: Users maintaining legacy serial equipment who need a configurable, single-port USB serial connection. Users requiring multiple ports, native USB-C, galvanic isolation, or specialized industrial voltage protection may need a different adapter category.

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Faqs

How do I set up the startech.com USB To Serial Adapter Cable ICUSB232V2 for the first time?

Download the ICUSB232V2 driver package from StarTech.com before connecting the adapter. Extract the downloaded file, open the folder matching your operating system, and run the installer. After installation, connect the USB Type-A plug to the computer and the DB9 connector to the RS232 device. On Windows, open Device Manager and check Ports (COM & LPT) to identify the assigned COM port, then select that port in your terminal or device-management software.

What should I do if the startech.com USB To Serial Adapter Cable ICUSB232V2 is not detected?

Try another working USB port, preferably directly on the computer rather than through an unpowered hub. Reinstall the Prolific PL2303 driver and restart the computer after installation. In Windows Device Manager, check Ports (COM & LPT) for the adapter or a yellow warning icon. If the COM port appears, configure your application to use that exact number. Also inspect the USB connector and DB9 plug for looseness, bent pins, or visible damage.

How can I fix garbled data or unreadable characters with the ICUSB232V2 serial adapter?

Garbled serial output usually means the computer and connected RS232 device use different communication settings. Confirm the baud rate, data bits, parity, stop bits, and flow-control method in the device manual, then enter identical values in your terminal software. Common settings are not universal, so do not assume the correct baud rate. If the settings are correct, reconnect both ends, test a shorter serial cable, and verify that the equipment uses RS232 rather than another serial standard.

Which operating systems and devices are compatible with the startech.com USB To Serial Adapter Cable ICUSB232V2?

The ICUSB232V2 is designed to add one RS232 DB9 serial port to a computer with a USB Type-A port. Published compatibility includes supported Windows, macOS, and Linux versions, but driver availability can vary by operating-system release. It can connect equipment such as serial terminals, modems, point-of-sale hardware, and industrial controllers. Check the current StarTech driver package before deployment, especially on newer operating systems or computers without native USB Type-A ports.

What are the main features of the startech.com USB To Serial Adapter Cable ICUSB232V2?

The ICUSB232V2 converts a computer's USB connection into one male DB9 RS232 serial port. Its Prolific PL2303 chipset, 512-byte FIFO buffer, and support for baud rates up to 921.6 Kbps are intended for reliable serial communication. The adapter supports configurable data bits, parity, stop bits, and flow-control options through compatible software. It is useful for legacy equipment that lacks USB connectivity but requires a standard RS232 interface.

How do I change the COM port number assigned to the ICUSB232V2?

In Windows, connect the adapter, open Device Manager, expand Ports (COM & LPT), and open the adapter's Properties. Select the Port Settings tab, choose Advanced, and select an unused COM port number. Confirm the changes, disconnect and reconnect the adapter if necessary, and update the serial application to use the new number. Avoid assigning a port already used by another device, and remember that some older software only accepts low COM numbers.

Can the startech.com USB To Serial Adapter Cable ICUSB232V2 achieve its maximum serial speed with every device?

No. The adapter supports a maximum baud rate of up to 921.6 Kbps, but the actual speed depends on the connected RS232 equipment, application, driver, cable quality, and communication settings. Both devices must support and use the same baud rate. For unstable communication, reduce the speed and test again, then verify flow control and buffer settings. High-speed operation is practical only when the connected hardware and software are designed for it.

How should I maintain and store the ICUSB232V2 USB to RS232 adapter cable?

Keep the adapter dry, clean, and away from excessive heat, dust, and electromagnetic interference. Disconnect it by gripping the connector housing rather than pulling the cable, and avoid sharply bending the cable near either plug. When storing it, loosely coil the cable without tight kinks and protect the DB9 pins from impact. If communication becomes intermittent, inspect and gently clean the connectors with appropriate electronics-safe materials, then check for damaged pins or cable strain.