Serial null modem adapter StarTech DB9 RS232 M/M, DB-9 male to DB-9 male, white

StarTech DB9 RS232 serial null modem adapter (male-to-male) allows two DB-9 serial ports to be connected directly by cross-wiring transmit and receive lines. The adapter uses DB9 male connectors on both ends with a white housing and is intended for use with legacy RS232 equipment and point-to-point serial links where a null modem connection is required.

Advantages

The adapter provides a cost-effective way to convert a straight-through DB9 cable into a null modem connection without requiring a dedicated null modem cable. Its compact in-line form factor ensures easy insertion between standard DB9 connectors, and the product is backed by lifetime warranty and free lifetime technical support from the manufacturer.

Suitable for

• Connecting two RS232 devices directly (PC-to-PC, PC-to-router console)
• Device configuration and debugging of legacy equipment
• Point-to-point serial communication and data transfer
• Temporary or field installations where a full null modem cable is not available

Key specifications

• Connector type: DB9 male to DB9 male
• Signal standard: RS232 (null modem cross-wiring)
• Housing color: white
• Form factor: in-line adapter
• Use case: serial null modem (crossed TX/RX)

How to use

Connect each DB9 male end of the adapter into the corresponding DB9 female port of the two devices you want to link. The adapter cross‑wires the transmit and receive lines required for a null modem connection, allowing direct serial communication without modifying existing cables. Ensure both devices are configured for matching serial settings (baud rate, parity, data bits, stop bits) before starting communication.

Usage recommendations

Use this adapter with standard DB9 serial ports and keep cable lengths within recommended RS232 distances for reliable communication; verify device serial settings and, if needed, use shielding or ferrite cores in electrically noisy environments.