Definition of media-dependent adapter (MDA) in Network Encyclopedia.
What is MDA (media-dependent adapter)?
MDA (Media-Dependent Adapter) is a module that can be inserted into a modular Ethernet switch to provide connectivity between different media types. Modular Ethernet switches typically have two to four media-dependent adapter (MDA) slots on the front panel, where you can easily insert and remove MDAs for providing various media connectivity configurations.

- Eight 10BaseT ports
- Two 100BaseTX or 100BaseFX ports
- A Fiber Distributed Data Interface (FDDI) double-ring connection
By selecting and inserting different MDAs into a modular switch, you can quickly reconfigure complex Ethernet networks. Bridging between the different types of media is performed internally by the chassis circuitry inside the switch.