A hot docking mechanism enables a PCI type card with an edge connector to be inserted into an enclosure and docked in a card socket on the motherboard without operator access to the enclosure interior. A card holder carries the card and is supported on a card guide for sliding motion into the enclosure to a position at which the edge connector is aligned with the socket secured to the device motherboard. A camming assembly includes a cam lever extending outside the enclosure to convert horizontal or pivoting motion of the cam lever to vertical motion of the card into and out of the socket. The camming assembly, mounted above and proximate the mother board surface, increases mechanical advantage during docking and undocking. The card is supported within the card holder and the camming connection between the card and camming assembly is disposed intermediate the longitudinal ends of the socket to maximize mechanical advantage and minimize misalignment during card docking and undocking.