BlackBox, EYN257T-0010-MF, DB9 Serial Null-Modem Cable, DB9 Male/DB9 Female, 10 (3.0-m) Download files quickly and easily between AT computers. Features: Ideal for AT-to-AT file transfers. Gray PVC jacket with metal (EMI/RFI) hoods. Has 115-ohm nominal impedance at 1 MHz or above. Crosses Pins 2 and 3 for RS-232 standards compliance. Guaranteed for life!