The E model can read the B formatted cartridge.
The E model writes in 256 track format only and can not write or append to a B
formatted tape.
The E model can reformat a B format tape and then can write in the E format.
The B model can not read E formatted data.
The B model can reformat an E format tape and then can write in the B format
     (The B model device must be a minimum device code level ( A_39F or B_731)
     to do so).

I hope this helps.

Carlos Raso
ISASA