C2G 52179 Serial RS232 DB9 Null Modem Cable with Low Profile Connectors F/F, In-Wall CMG-Rated, Black (25 Feet, 7.62 Meters) In-wall, CL2-rated jacket Null modem wiring scheme Low profile connectors Fully shielded to prevent unwanted EMI/RFI interference The transmit and receive signals are crossed to ensure proper data transmission