16 inch Null Modem Cable DB9 RS-232 Male/Male 8 Conductor – Campbell Scientific
The DB9 Serial Null Modem Cable is a specialized RS-232 serial cable with cross-wired pins. Null Modem Cable Internally crosses the Tx (Transmit) and Rx (Receive) lines. The Tx of the first connector links to the Rx of the second connector, and vice versa.