StarTech.com 1m USB to Null Modem Serial Adapter Cable BlackAdd RS 232 DCE serial communications support to a desktop or laptop computer and resolve DCE DTE conflicts directly without the need for additional cross wired serial cables or adapters. The 3. 3ft (1m) Null Modem USB Serial Adapter adds an RS 232 serial DB DE 9 (female) connector to a desktop or laptop via a USB Type A port. Secure the adapter to a serial device, using pre installed and removable slotted D Sub thumbscrews or install the included DB 9