Q.
Does the iDR system support digital input/output? 
 

A.
The iDR system has digital buss connections for connecting digital signals to/from the iDR-In, iDR-Out and other iDR-8 units,
but at the time of writing (February 2004) there are no direct methods of connecting digital i/o such as SPDIF, TOSLINK, AES3 (AES/EBU) etc. 


MARCH 2009 : there are now digital versions of iDR-IN and iDR-OUT, 
these have the same chassis and appearance of the analogue versions but have AES/EBU connectors on the rear.    

More information is available online here 
iDR D-in
iDR D-out