The ESX-8GT is an expansion module for the ES-4, ES-40, ES-5 or FHX-8GT, adding 8 on/off outputs for use as gates, triggers, clocks etc. from one expansion header.

The ES-4/5 Controller software (part of Expert Sleepers ) also allows the ESX-8GT outputs to be used for DIN sync or 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. See the  page for the necessary cables. Note there is also the  module, which is dedicated to MIDI and DINsync duties.

* Note - the MIDI out feature is only officially supported at sample rates of 48kHz and above, though some users  with specific hardware when running at 44.1kHz. The  module works for MIDI output at all sample rates.