A passive cable adaptor for connecting a data source device with a display device is described. The adaptor has a packet-based interface connector at one end, the connector having a positive main link pin, a negative main link pin, a positive auxiliary channel pin, and a negative auxiliary channel pin. At the other end is a micro serial interface connector, wherein multimedia content is transmitted over the cable adaptor and electrical power is supplied over the cable adaptor simultaneously. The cable adaptor has an auxiliary and hot plug detect (HPD) controller utilized to map the auxiliary channel and HPD signals of the packet-based digital display to the micro serial interface ID signal.