The DataPro 6635 series cable is a replacement cable for the Cisco CAB-SS-V35MT cable, one of the Cisco family of "Smart Serial" cables.
The router end terminates in a Foxconn High-Density 26-pin male connector, the WAN end terminates in a 34-pin male Winchester type V.35 connector.
The connectors are: Foxconn DF26M and V.35M. Connector Diagrams: Foxconn [N/A] and V.35M.