A host device comprises a controller and a connector. The host connector comprises fixed-function and multi-function pins. A first group of host connector pins comprises one or more of the fixed-function pins and a second group of pins comprises the remainder of the fixed-function pins and the multi-function pins. The host connector can be releasably attached to a connector of an accessory device. The first group of host connector pins can be used to discover the functions of the accessory connector. The host device can select functions to be enabled at the host and accessory connectors from among the functions mutually supported by the two connectors. The host can enable the selected functions at the host connector and can instruct the accessory to enable the selected functions at the accessory connector. The host can reconfigure host connector functions in response to a different accessory being attached to the host.