Sense Byte 21 (Thread And Load Diagnostics); Sense Byte 22 (Field Replaceable Unit Identification); Sense Byte 23 (Field Replaceable Unit Identification) - IBM 3803 Manual

Sense Byte 21 (Thread and Load Diagnostics)
Bit
0
1
2
3
4
5
6
7
Designation
LOAD Button Depressed
Left Reel Turning
Right Reel Turning
Tape Present
Reels Loaded
Load/Rewind
Load Complete
Load Check
Sense Byte 22 (Field Replaceable Unit Identification)
Sense Byte 23 (Field Replaceable Unit Identification)
Section 4: Status and Sense Information
49