A first connector assembly may be connectable to a second connector assembly using a sliding attachment process, in which a front portion of the first connector assembly is inserted into an end of a slot in the second connector assembly and slides laterally along the slot until electrical contacts on the two connector assemblies are aligned. Electrical contacts of the first connector assembly may be biased proud to make contact with recessed electrical contacts in the second connector assembly. A retraction mechanism may be provided to retract the electrical contacts of the first connector assembly during lateral sliding. An interlock mechanism may be provided to prevent unwanted operation of the retraction mechanism.