Key to features:

Level:
1
introductory u'grad
3
intermediate u'grad
4
upper-level u'grad
5
graduate

Textbook use:
P
principal textbook
S
supplement

Enhancements:
SA
streaming audio
SV
streaming video
L
Internet links
E
online exam
M
message boards
C
chat rooms
G
gradebook
CD
supp. CDs
H
supp. hard copy