Focusrite Octopre LE - the digital option
The Focusrite Octopre LE 8-channel microphone preamplifier has the option of a digital output for direct connection to your digital audio workstation.
Upmarket audio interfaces have audio inputs in plentiful supply, but interfaces at a lower price point, such as the Digidesign Digi 002 often have fewer microphone inputs. The components cost money, the connectors cost money, the controls take up panel space. You can see why.
So putting digital outputs on an 8-channel microphone preamplifier makes excellent sense. Going back to the example of the Digi 002, you can use the Focusrite Octopre LE to give the 002 eight additional inputs to make it a very versatile unit capable of recording an entire band, or even orchestra.
The digital interface on the Focusrite Octopre LE takes the form of the ADAT 'lightpipe' optical connection. This was originally developed for the Alesis ADAT 8-track digital tape recorder, which to be honest wasn't reliable enough for the job it was expected to perform. But Alesis certainly got things right with the connection. The ADAT lightpipe is cheap for manufacturers to implement, and effective in use over short distances.
The Octopre LE is capable of working at either 44.1 kHz or 48 kHz sampling rates, at 24-bit resolution. You could wonder why a 96 kHz option is not provided. One good answer is that this is not an expensive unit to buy, and also a sample rate of 96 kHz places too much of a data bandwidth strain on most multitrack recording systems.
Any digital audio device should have a word clock input, so it can synchronize to other devices, or to a master clock. The clock input will accept 44.1 or 48 kHz, or 256x if needed. There is also a clock output.
A final finesse on the Focusrite Octopre LE's digital option is the ability to accept an 8-channel digital input on an ADAT connector, and convert this back to analog signals available on the line outputs, switchable in groups of four channels. This could be useful, for example, to connect a DAW to an analog mixing console for playback in a live sound or theater context. The feature can also be used for up to 7.1 channel surround monitoring. It can't have cost much to implement, so it's a sign of good thinking in the design department.