An interpreter adds printing to punched but otherwise blank cards, based on
what's punched on each card. Most were not capable of reading or
interpreting all 80 columns of a card. Thus the desired fields had to be
selected by wiring the control panel appropriately. In any case, the
printing characters were wider than the card columns, and did not line up.
The 551 and 552 models, by allowing more than one row to be printed, also
allowed interpretation of all 80 card columns by running the cards through
twice with different column and row selections. The 551 requires one pass
for each of up to 5 rows that is to be printed. The printing row is
selected by a knob, shown below. On the 557, up to 25 rows can be printed
in a signle pass. The print mechanism is a type bar; this is not dot-matrix
printing as on the key punch, which differs from
the printing on interpreted cards with its 1-to-1 correspondence with the
CLICK ON ANY IMAGE to enlarge.
Here's a table summarizing what I can find out about different IBM interpreter
Check Writing Interpreter
How many card columns can be interpreted in one pass.
On how many different rows can printing be done?
How many cards can go in the card (input) feed.
How many cards can go in the (output) stacker.
Throughput, cards per minute.
The 551 or its successors (if any) is/are known to millions of people who
received US government or other checks printed on IBM cards or punched-card
bills from public utitilities up until the not-too-distant past. Special
features of the 551 included regular plus double-width type (e.g. to
emphasize the amount of a check) and automatic asterisk fill (to prevent
additional digits from being added after the fact), as shown in the
following sample check:
IBM Card Interpreters, Types 550, 551, and 552 - Principles of
Operation, Form 22-3178-3 (Copyright 1946, 3rd Edition: May 1954).
All photos except the 557 are from this manual.
IBM 548,552 Interpreters - Manual of Operation,
IBM Data Processing Division, 112 East Post Road, White Plains, New York,
Form 224-6384-2 (Copyright 1946, 1958)
IBM 557 Alphabetic Interpreter Reference Manual
(Copyright 1954, 1958, 1959).