UGREEN DB9 RS232 Female-to-Female Cable, 1.5 m (20149)

Overview

The UGREEN 20149 links two devices that both have DB9 male serial (RS232) ports, for example a computer or serial adapter and a controller, instrument, modem or point-of-sale device. It is a 1.5 m female to female cable wired straight through, with thumb screws at both ends. It suits desk, rack, laboratory and industrial-instrument connections where the equipment manual calls for a straight-through cable.

Is it right for you?

• Suits two devices with DB9 male ports and true RS232 electrical interfaces whose manuals specify a straight one-to-one connection.
• Not for pairs of devices that need a null modem (crossover) cable, as it does not cross transmit and receive.
• A computer needs an existing RS232 port or a separate compatible serial adapter. The cable does not create a COM port from USB.
• The operating system does not matter to the cable itself. The serial port hardware, the application and the device protocol decide whether the link works.

Key features

• DB9 female connectors at both ends for equipment with DB9 male ports.
• Straight-through signal path that keeps the endpoint wiring rather than crossing transmit and receive.
• 1.5 m length for desk, rack, laboratory and instrument connections.
• Thumb screws on both connectors to resist accidental unplugging and vibration.
• Foil shielding and moulded connector shells for ordinary signal protection and handling.
• Passive construction: no driver, because it adds no electronic interface. About 150 g.

What else you need

Two devices with DB9 male RS232 ports whose transmit, receive and handshake roles work through a straight one-to-one path, both set to matching baud rate, data bits, parity, stop bits and flow control. If a computer has no serial port, it needs a separate serial adapter whose connector gender, RS232 standard, driver and wiring match.

Installation

Plug each end in and tighten the thumb screws by hand. Route the cable with strain relief so it is not pulled at the connectors.

Before you buy

• DB9 is a connector shape, not a guarantee of RS232. Confirm true RS232 electrical levels on both sides.
• Straight-through and null modem cables are not interchangeable. The wrong wiring usually stops communication and can be unsafe for sensitive equipment.
• Some manufacturers use proprietary DB9 pin assignments. Follow the equipment pinout rather than assuming a universal layout.
• The passive cable cannot isolate ground potential or suppress severe industrial electrical noise.
• It does not create a COM port from USB, does not supply power to either device and does not convert RS232 to TTL UART, RS422, RS485, Ethernet, VGA or parallel.
• It cannot correct mismatched baud, parity, stop bit or flow control settings, and it does not guarantee that proprietary equipment uses all nine pins the same way.
• The screw locks stop casual unplugging but do not make it safe to hang equipment from the cable.
• Disconnect and investigate any abnormal heat, odour, visible damage or repeated communication errors.
• The box holds the cable only: no USB to serial converter, null modem adapter, gender changer, power supply or serial software.
• Check before ordering: both device ports are DB9 male, both use true RS232 signalling, the manuals specify straight-through rather than null modem, the pin assignment and DTE/DCE roles are compatible, 1.5 m is the right installed length, and both endpoints can be set to matching baud, framing and flow control.