The 2408mk3 Expansion Interface from MOTU adds all of the inputs and outputs of the 2408mk3 core system for users of an existing PCI-424 based MOTU audio systems (2408mk3, 24I/O, HD192, etc.). The unit is exactly the same interface that comes with the PCI-424 system and provides 8 channels of pristine 24-bit/96kHz analog input and output, combined with 24 channels of ADAT and Tascam digital I/O. (Only a total of 24 inputs can be used simultaneously, but across all formats.)
In addition to the analog outputs, the interface also features a stereo output with front panel volume control so one can plug powered monitors directly into the interface, while a separate headphone output with volume control is on the front panel. S/PDIF digital I/O is also provided for exchanging digital audio with a wide variety of other devices. An extra S/PDIF stereo output of the main mix is available that could, for example, be left connected to a DAT machine.
The 2408 mk3 interface can also function as a standalone format converter. The addition of the expander is as simple as connecting the supplied Audio Wire cable to one of the free terminals on the host PCI 424 card.