The ES-6 is the counterpart to the ES-3 Lightpipe/CV Interface, offering up to 8 channels of CV input with output via an optical lightpipe connection. As with the ES-3, the ES-6 also works well for audio signals, with conversion quality on a par with a regular audio interface (see here or here).
The ES-6 itself has 6 input sockets; the remaining 2 channels are provided by an expansion module e.g. the ES-7.
Please note that a connected ES-3 or ES-8 is required for operation. The ES-6 gets its clock signals from the ES-3 (which derives them from its lightpipe input) or ES-8 (which has an internal clock).
Header for connecting expansion modules e.g. the ES-7
Current draw: 103mA on the +12V rail, 52mA on the -12V rail
The front panel is drilled for both Doepfer and Analogue Systems mounting holes (using a 'slot' rather than a single round hole). The power connector is a Doepfer standard 16 way IDC, with -12V furthest from the top of the board.
Note that connection to the ES-3 is by a simple plug-in cable for the ES-3 mk2 and above. The original ES-3 requires some soldering to add the required connections.