The Mix In connection on the 302 and 442 Field Mixers is an unbalanced stereo TA3 Male input designed to link multiple Sound Devices field mixers. This connection routes signals directly to the Master Output Bus and is designed to interconnect with the Tape Out/Mix Out of Sound Devices MixPre, 302, and 442 mixers. There are no level controls on Mix In signals, so levels must be controlled at the source.
In addition to multi-unit linking, the Mix In connection is used as inputs from devices that only have line level outputs such as the Sound Devices MM-1 and MP-1. The diagrams below indicate the connections necessary for an XLR Line Output to the TA3 Mix In of a 302 or 442 Field Mixer. Note that the shell of the TA3 connector must be grounded to Pin-1 to open the connection.