These T1, RJ45-RJ45 ( RJ48C ) cross-over Ethernet cables are constructed with premium Quabbin 9720, T1 certified cable. Two individually shielded, 22 AWG, 100 ohm pairs maximize the performance of your expensive T1 circuits and equipment. Beware of generic T1 Ethernet cables made with inexpensive Cat5 unshielded Ethernet cable. The American National Standards Institute (ANSI) states in ANSI T1.403 that T1 cable be constructed of two balanced pairs, 22 AWG Solid conductor, 100 ohm impedance, with a loss budget of 5.5 db. Cross-over wiring configuration available in 3-foot (0.9-meter), 5-foot (1.5-meter), 7-foot (2.1-meter) and 10-foot (3.1-meter) lengths. Custom lengths available. Consult your reseller. Also available in straight-through wiring configuration. See N265-Series T1 Ethernet cables.