Back to back serial cables / back to back smart serial cables
back to back DB60 serial cable
A DB60 Back to back serial crossover cable is used with cisco 2500/2600/3600 routers, WIC-1T, NM-4A/S, NM-8A/S AND NM-4T. It is equivalent to connecting together a CAB-V35FC and a CAB-V35MT cable back to back.
back to back smart serial cable
Smart Serial DTE Interface To Smart Serial DCE Interface Crossover Cable. Connect any combination of routers with WIC-2T cards installed back to back. It is equivalent to connecting together a CAB-SS-V35FC and a CAB-SS-V35MT cable back to back.