A card edge connector for printed circuit boards is disclosed which employs a double-decker design. The connector may have the same length and width as conventional connectors used on Industry Standard Architecture (ISA) personal computers but is deeper. Conventional 8- and 16-bit ISA accessory circuit boards may be plugged into a corresponding socket which is also disclosed herein until they reach a stop upon which they rest, working as they would in an ISA personal computer. 32-bit Extended Industry Standard Architecture accessory circuit boards have a second row of connectors and a notch so they slide farther down into the socket, lining up with a second row of contacts. This design uses less physical space for connectors, allowing more room for logic circuitry on the motherboard.