UGREEN CR104 USB-A to RS232 DB9 Adapter with PL2303, 3 m (20223)

Overview

The UGREEN CR104 (20223) connects a computer that has no serial port to RS232 equipment such as tills, barcode scanners, PLCs, modems, printers and lab instruments. It plugs into a USB-A port, appears to the computer as a serial COM port, and ends in a DB9 male connector with thumb screws on a 3 m lead. The 3 m length suits a fixed desk where the computer sits away from the till or instrument, and for a service kit.

Is it right for you?

• Suits equipment whose manual specifies a true RS232 port with a DB9 female connector, on a Windows, macOS or Linux computer with USB-A and a current PL2303 driver.
• Not for TTL-level UART, RS422 or RS485 devices, Ethernet or RJ45 console ports, parallel printers or video: the DB9 shape alone does not mean RS232.
• DTE-to-DTE equipment may need a separate null-modem crossover adapter; this cable is wired straight through.
• A USB-C only computer needs a proven data-capable host adapter.

Key features

• Prolific PL2303 controller presents a virtual COM or tty port to the operating system.
• USB 2.0 host interface with serial rates up to 1 Mbps in a compatible setup.
• Standard nine-signal DB9 assignment: 1 DCD, 2 RXD, 3 TXD, 4 DTR, 5 GND, 6 DSR, 7 RTS, 8 CTS, 9 RI, so hardware handshaking works for equipment that uses it.
• Shielded 3 m cable with moulded strain relief and thumb screws for a secure equipment-side connection.
• Powered from the USB port; 163 g.

What else you need

A PL2303 driver for your operating system version, a serial application that can select the COM port, and the equipment’s serial settings (baud rate, data bits, parity, stop bits and flow control). The connected equipment needs its own power; the adapter powers only its own electronics.

Installation

Install the PL2303 driver if the system does not load one, plug the adapter into USB-A, screw the DB9 connector to the equipment and set the port parameters in your application. Virtual machines, locked-down corporate systems and USB hubs may need administrator approval or USB pass-through.

Before you buy

• Confirm the target port is DB9 female and documented as true RS232, and that its wiring matches a straight-through DB9 male cable or you have the right crossover accessory.
• Use a PL2303 driver, not one meant only for a different USB-to-serial controller. Driver availability can change with operating system releases; check support for your version and security policy.
• A COM port appearing proves only that the adapter was detected, not that the equipment, pinout or settings are correct.
• Use the serial rate the equipment specifies; 1 Mbps depends on compatible hardware and settings.
• Wrong voltage levels, wiring or handshake settings can prevent communication and may damage sensitive equipment.
• Printed material, packaging and how the driver is supplied can vary. A null-modem adapter, USB-C host adapter and power supply for the serial equipment are not in the box.