The mobile daughter card, also known as an MDC or CDC (communications daughter card), is a notebook version of the AMR slot on the motherboard of a desktop computer.
It is designed to interface with special Ethernet (EDC), modem (MDC) or bluetooth (BDC) cards.
In 1999, Intel published a specification for mobile audio/modem daughter cards.
The document defines a standard connector (AMP* 3-179397-0), mechanical elements including several form factors, and electrical interface.
The 30-pin connector carries power, several audio channels and AC-Link serial data.