A modular signal interface system for providing electrical communication with a surgical instrument when the surgical instrument is inserted into a cannula of a trocar. The system includes a signal interface adapter and an instrument connector. The signal interface adapter is provided on, or adapted to be mounted on a trocar, and includes central aperture extending therethrough and a proximal face having a plurality of conductive contacts. The instrument connector is provided on or adapted to be mounted on a shaft of a surgical instrument, and includes a central aperture extending therethrough and a distal face having a plurality of conductive contacts. The signal interface adapter and the instrument connector are adapted for mating engagement such that, when matingly engaged, their central apertures are axially aligned and predetermined ones of the plurality of contacts of the signal interface adapter are in conductive contact with predetermined ones of the plurality of contacts of the instrument connector.
