A medical device, such as an electrosurgical scalpel, having a base unit and one or more attachable implements for performing medical procedures. The device include a host controllable module for capturing images of the attachable implement, decoding information contained in the image, and reporting the results of the decoding to the medical device. The host controllable module includes a system microcontroller that interconnects an optical imager and/or an RFID transceiver through the single interface to the host medical device. As a result, the module may be easily retrofit into existing medical devices and programmed to perform operations on legacy instruments as well as additional functions not previously available to the medical device.