Honeywell 400 Series Hardware Manual page 85

Data Formats
Subsystem States
Checking
Complete reliability of the punch is guaranteed by a read-after-punch feature. This reading
station examines the parity of each punched row to determine if the correct number of
holes has actually been punched.
The following punch conditions are also checked:
Punch ready or busy.
Attention--hopper empty, stacker full, feed alert, chad box missing or full, card jam,
manual halt.
Data Alert--punch instruction or data not received in time, parity error, punch error.
Instruction rejected.
Punch absent or off line.
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