FWIW, it is NOT EBCIDC, and has upper/lower case state
which
has to be remembered.
How many track is this tape? seems like most solutions suggested so far are
for 8-track and I ISTR that Atlas normally used 7-track but I thought only
5-t used shifts. Internally Atlas probably used a 3-shift code (as later
used by the 1900 for paper-tape) with 6-bit characters as was common for
computers in those pre-ascii days.
If it is 5-track a greater degree of care will be required with the use of a
winder as that narrow tape twisted and snarled-up so much more easily than
the wider forms.
Andy