The ESX-8MD is an expansion module for the ES-4, ES-40 or ES-5, adding eight MIDI/DINsync outputs from one expansion header.

The ES-4/5 Controller software (part of Expert Sleepers Silent Way) allows the ESX-8MD outputs to be used for MIDI output (note - not just MIDI clock output, but as an actual MIDI port, capable of sending any MIDI messages). Since these outputs are driven from an audio connection, they have sample-accurate timing, which no USB MIDI interface can claim.

The Silent Way Sync plug-in would typically be used to send DINsync to the ESX-8MD, though any software capable of addressing the ES-4/5's expansion headers, via Silent Way or the Max/MSP external, can send clock pulses to it.