If you own old gear it will be hard to source spare parts. The contacts of the cable connecting my mount with the hand control are full of rust. Since I couldn't find any commercially available cable I put it together myself without a solder iron. The unused pins can be cut and the protrusing cables isolated with tape. Cable and connector are about US$10.
Mount: Orion Atlas EQ-G
Hand Control: SynScan V3
Cable: RJ45 (8p) to RS-232C (male)
Pin assignment:
Note that the colors of the cables inside the RS-232C connector may differ by vendor.