An electrical connector for removably receiving a daughter card includes a first group of contact springs, which extend in their free, undeflected state into a card-receiving slot, and a second group of contact springs, which are displaced from this slot in their undeflected state. This connector also includes an actuator, which can be moved to engage the second group of contact springs so that they are moved into the card-receiving slot. The actuator can be left in a position in which it is not so engaged when a first type of daughter card is inserted in the connector, with slotted portions of the daughter card passing over surfaces of the actuator. The actuator is moved into this engagement with the insertion of a second type of daughter card as surfaces on the daughter card push on surfaces of the actuator. The actuator also includes means by which it is locked to this second type of daughter card so that it is restored to its unengaged position as the daughter card is withdrawn from the connector. In an alternative embodiment, the engagement of the actuator is not controlled by the surfaces of the daughter card, but rather by manual movement of an engagement lever.