Digital I/O; A Connecting The Digital Bus - Alesis BRC Reference Manual

Each slave ADAT's front panel will indicate the status of the
record/input enables and transport controls, and the track LED bar
graphs to reflect the corresponding track input/tape levels. The
numeric display on each slave ADAT unit will always show the
NORMAL time (absolute or relative) location of each tape, regardless
of the Display Type on the BRC (Normal, SMPTE or Bars; see section
1.4B).

2.2 DIGITAL I/O

With analog recording, bouncing tracks or backing up from one
multitrack to another loses one generation, which adds hiss and
distortion. With digital recording, such procedures will produce a
"clone" of the original. This makes it easy to create extra copies of
tracks or safety copies of entire tapes, or make multiple copies for
distribution. This is all done via the fiber optical digital bus, which
can carry as many as eight tracks from one ADAT to any other
ADAT(s) in the system, or to an Alesis AI-1 Digital Interface for
exporting to other digital recording equipment using AES/EBU or
S/PDIF formats.
For more information on digital busing, see section 4.7.

2.2A Connecting the Digital Bus

Digital busing requires a fiber optic cable for each ADAT in the system
(the digital bus does not connect to the BRC). This connection can be
made while power is on or off, and ADATs do not need to be turned
on in any particular order (see figure 1).
To connect the digital optical network:
1. Connect one end of the fiber optic cable into the optical output of
the first ADAT in the system. The cable is non-polarized, so either
end can be inserted into the optical output;
Note: If the other end of the cable is disconnected and a signal is being
sent through the cable, you will be able to see a red light at the
output. This is an LED and not a laser light, so you don't have to
worry about damage to your eyes.
2. Connect the other end of the fiber optic cable to the optical input
of the second ADAT in the system;
3. For each additional ADAT, connect one end of an additional fiber
optic cable to the first ADAT's optical out jack, and the other end
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