The DMC-842-M from RME is an 8-channel AES42 interface and control device for digital microphones. AES42-2001 is an extension of the current AES digital audio standard that provides the framework for interfacing and controlling professional digital microphones (not to be confused with the consumer type of USB equipped microphones).
The DMC-842-M supports both Mode 1 and Mode 2 operation. Depending on the mode implemented by the microphone's manufacturer, the unit can supply power to the microphone while also providing for the remote control of parameters. These include polar pattern, pre-attenuation, enabling a low cut filter, pre-amplification, mute and polarity, in addition to getting feedback about signal levels.
Mode 1 is a protocol that allows for supplying Digital Phantom Power (DPP), switchable per channel, but no control data can be transmitted to the microphone. Sample rate conversion is available on a per channel basis for situations where the use of multiple Mode 1 type microphones is required. Mode 2 allows microphones to be synchronized and control data to be sent. Either mode is available per channel.
The I64 MADI Card provides the DMC-842 with a 64-channel MADI input and output. The coaxial and optical outputs operate in parallel to the AES/EBU and ADAT output and deliver the same data. They also provide full redundancy by automatically switching from one input to the other in case of loss of one of the signals.
The MADI input can operate as an optional clock source as well as a through-input. Since each DMC-842 uses only 8 channels, up to 56 channels can be passed through. This is used to serially cascade several DMC-842s, allowing up to 8 devices to be connected serially. All 64 combined channels are available at the last device's MADI output.