Sony DAT DTC-690 Operating Instructions Manual page 55

You can record a digital audio tape recorded via analog input/output to another via digital input/output. But, you cannot make a
second generation tape via digital input/output.
Turntable
Tuner
Microphone amplifier
DAT deck
(playback)
DAT deck
(playback)
Remarks
There are no restrictions for generation when DAT decks are connected via analog input/output each other.
These rules does not apply when you use a DAT deck which does not adopt the Serial Copy Management System.
2
Analog input/output
Tape recorded via analog input/output
Coaxial digital cable
or
Optical digital cable Digital input/output
First generation tape
recorded via digital input/output
Coaxial digital cable
or
Digital input/output
Optical digital cable
(Recording is possible when connected via
analog input/output.)
DAT deck
DAT deck (recording)
DAT deck (recording)
55