Serial null-modem cable InLine B-12224, 9-pin female to female, 3 m

InLine B-12224 is a 3 m null-modem serial cable with 9-pin female connectors on both ends, designed for direct RS-232 device-to-device communication. The cable crosses transmit and receive lines to allow two DTE devices to exchange data without a modem or other intermediary. It is intended for configuration, diagnostics and low-speed data transfer between computers, industrial controllers, legacy peripherals and serial consoles.

Advantages

This null-modem cable provides simple, reliable wiring for RS-232 connections between two devices with DB9 female ports. The 3 m length offers flexibility to connect equipment across racks or workbenches while keeping signal attenuation low. The fixed crossover wiring eliminates the need to reconfigure ports or use adapters, and the standard 9-pin female connectors ensure compatibility with a wide range of legacy and industrial hardware.

Suitable for

• Connecting two PCs or laptops with serial ports for direct communication
• Linking industrial controllers and PLCs for configuration and diagnostics
• Interfacing with serial consoles on routers, switches and network devices
• Connecting legacy peripherals such as serial printers, modems or instrumentation
• Laboratory and workshop environments requiring simple RS-232 data exchange

Key specifications

• Cable type: null-modem (crossover) serial cable
• Connector type: 9-pin female (DB9) on both ends
• Length: 3 metres
• Signal standard: RS-232
• Wiring: transmit and receive lines crossed for DTE-to-DTE communication
• Shielding: braided or foil shield (manufacturer standard)

How to use

Plug each 9-pin female connector into the corresponding male serial port of the two devices you want to connect. Ensure both devices are powered off or their serial ports are inactive during connection to avoid unintended signals. Configure serial port parameters (baud rate, parity, data bits, stop bits and flow control) on both devices to match prior to data exchange. Use terminal software or device-specific configuration tools to perform diagnostics, transfer data or adjust settings over the RS-232 link.

Recommendations

Position the cable away from heavy electrical interference sources such as large motors or mains transformers to reduce noise. For longer-term installations in industrial settings, verify connector retention and consider strain relief to avoid mechanical stress. If higher data rates or longer distances are required, evaluate alternative interfaces or signal repeaters.