Digital i/o?
The 66 has the s/pdif standard of digital i/o on rca coax connectors. It does not have the optical (lightpipe/ Toslink/ ADAT) form. The Delta s/pdif carries a normal stereo signal, but it can be used as 2 mono channels in your recording software.
Certain equipment have digital outs - Standalone mulitrack recorders, effects units, amp modellers etc. You can record the s/pdif input seperately so if you do have or get something with s/pdif coax output, you can avoid an analog conversion when recording it.
The s/pdif is an extra stereo channel, so you can actually record 6 tracks at once when using it.
The output could be used to feed studio monitors with digital inputs.
S/pdif output can also carry an AC3 surround sound channel for feeding to an external surround decoder box and speakers.
If you want an extra soundcard later, the second card can have its timing slaved to the first by linking the s/pdif. This makes the two cards act as one and ensures tracks split across the cards channels stay in time with each other. In fact, you can have up to 4 Delta cards working this way, all controlled from the same driver. NOT THE 44 though!
... although, the drivers are supposed to have something called "kernal sync" to synchronise the 44's. Some have it working and some are suspicious. Have not tried it myself.
The one downside to using the s/pdif input is that the card has to be switched in its control panel application (known as the Delta Panel - this has all the card driver and hardware settings), to run at the incoming s/pdif sample-rate clock.
If the external unit only has 48Khz, then the recording project will have to be at 48Khz, as the analog converters on the card will also be using that external audio clock.
