UGREEN USB to DB9 RS-232 Adapter Cable 1.5m

UGREEN USB to DB9 RS-232 Adapter Cable 1.5m

The UGREEN USB to RS232 DB9 male adapter cable (model CR104, SKU 20211) is a USB 2.0 Type-A to 9-pin DB9 male serial converter that adds an RS232 COM port to any laptop or desktop equipped with a USB-A port. It terminates in a DB9 male plug at the device end — the correct polarity for connecting to equipment that presents a DB9 female receptacle, including serial-equipped PCs, PLC controllers, access control panels, network switches with serial management ports, electronic scales, and ERP peripherals. A Prolific PL2303 chipset handles the USB-to-RS232 signal conversion internally, registering as a virtual COM port on the host OS without requiring an external power adapter.

DB9 Male vs DB9 Female: Choosing the Right Variant

The CR104 family covers both DB9 polarities, and selecting the correct one depends entirely on the port presented by the target device. A DB9 female receptacle on the device requires a DB9 male plug on the cable — that is this product (SKU 20211). Conversely, a DB9 male plug on the device requires a DB9 female receptacle on the cable (SKU 20201). Additionally, gold-plated contacts on the DB9 male end of this variant provide better corrosion resistance than the nickel-plated contacts on the female variant — an advantage in high-humidity or industrial environments where connector oxidation accelerates.

The cable otherwise shares all construction and performance characteristics with the female variant: PL2303 chipset, 24AWG/28AWG tinned copper conductors, triple-layer EMI/RFI shielding, 1Mbps maximum serial transfer rate, and bus-powered operation. Both register as a virtual COM port on Windows, macOS, and Linux without driver installation on Windows 8 and later. Furthermore, COM port number and baud rate settings are fully configurable through Device Manager on Windows or the equivalent system utility on macOS and Linux.

PL2303 Chipset Reliability in Professional Environments

The Prolific PL2303 remains the widely deployed reference chipset for USB-to-serial conversion in industrial and professional applications. It carries native driver support in Windows 8 through Windows 11, macOS X 10.6 and later, and the Linux 2.4 kernel and above. For Windows 7 and XP deployments — still common in legacy industrial and POS environments — a one-time driver installation from Prolific’s official package is required. The triple-shielded cable construction prevents the signal degradation and data loss that occur when unshielded serial cables run near power equipment, variable-frequency drives, or fluorescent lighting — common interference sources in the manufacturing and retail environments where RS232 serial equipment is most frequently found.

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Technical Specifications

Connectors

Performance

Cable Construction

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OS Compatibility

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Use Cases & Applications

Connecting to Serial-Equipped PCs and Servers

Legacy desktop computers, rack-mounted servers, and embedded PCs with native 9-pin DB9 COM ports present a female receptacle. A technician using a modern laptop without a native serial port uses the CR104 20211 to establish the male-to-female connection needed to communicate with these systems for configuration, diagnostic logging, or data extraction. This is common in industrial automation environments where production control computers have not been replaced and still run Windows XP or Windows 7.

PLC and Access Control System Programming

Programmable logic controllers from Siemens, Allen-Bradley, Mitsubishi, and others — as well as access control panels from HID, Suprema, and similar vendors — frequently expose a DB9 female programming port. Field engineers and commissioning technicians connect a laptop via the CR104 20211 to upload or download programs, configure parameters, and perform diagnostics using vendor-specific software. The gold-plated contacts are particularly valuable in these environments, where cables are connected and disconnected repeatedly across multiple site visits.

ERP Electronic Scale and POS Integration

Weighing scales used in warehousing, retail, and food processing environments commonly connect to ERP and inventory management systems via RS232 serial. These scales typically present a DB9 female port, requiring a DB9 male plug on the connecting cable. The CR104 20211 bridges the scale’s serial port to a USB-equipped host running the ERP software, transmitting weight data to the application via a virtual COM port at the baud rate configured in the scale’s firmware.

Network Switch and Router Serial Management

Some managed network switches and routers provide an out-of-band DB9 female serial management port as a fallback when the network interface is unavailable. The CR104 20211 provides the male plug required to connect a laptop for serial console access to these devices, complementing the RJ45-based console access provided by the UGREEN USB to RJ45 Console Cable (SKU 50773) for Cisco-standard equipment.