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difference is that the swiitch settings are made to ac-
commodate the line-loop operation and the line-
reader-start button is used. Because single-cycle op-
eration reduces throughput, corrections should be
made in home loop to reduce line time whenever
possible.
Correctfon Procedures
Both home-loop and line-loop correction procedures
are based on the use of only one reader and one punch
for any particular application.
Correction Procedure for Home-Loop Ope·ration
The
CORRECT
button (home-correction special feature)
provides an automatic tape-error-correction procedure
when tape is being punched. If data from a reader is
interspersed with keyed data in the output record,
pressing this button causes the reader to automatically
reread. When the
CORRECT
button is pressed:
1. The tape advances one additional column and a
hole is punched in the 8th track of the tape.
2. The tape punch feeds in the reverse direction until
the previous 8th track punch is sensed (a CR/LF
code is also punched in this tape column).
Note: With the home or line correction special feature, a
punch is placed in the 8th track when a carrier return and
line feed occurs.
3. Starting with the CR/LF code, the tape punch ad-
vances over the error item, punching delete codes
over the entire error record. (If the card punch is
used, the error card is ejected and a new card is reg-
istered at the punch station.)
4. When the tape punch completes deleting the error
record in the tape,
a. the card reader automatically recycles and the
card is reread (if neither an EOB code nor the
last card column has been read), or
b. the tape reader will automatically backspace to
the previous 8th track punch and then reread the
tape.
Note: If home-component-recognition is installed, and
the system is operating in the
DUP
mode, the readers and
punches that are in use must first have been selected in
the program mode using the component-recognition
codes.
The tape punch identifies the start of each new line
by the presence of a CR/LF code. The punching of this
code-into tape is initiated by either reading or keying
of the CR/LF code. Therefore, column one of each doc-
ument to be transmitted should contain this code. This
technique provides a carriage return and line feed
operation for each new line and ensures the correct
positioning of the print element for each corrected line.
If the data line to be corrected contains data trans-
mitted from two readers, the
CORRECT
button should
not be used. Because operating the
CORRECT
button will
control only the reader operating at that specific time,
only a portion of the line in error will be retransmitted.
In all cases where a data line contains information
transmitted from two readers, the manual correction
procedure is:
1. Reposition both readers to the end of the last cor-
rectly transmitted line. For a card reader, press the
eject button and place the ejected card in the hop-
per as the first card to be read.
2. Reposition the punched paper tape to the start of
the line in error. This is identified by the last 8th
track punch.
3. Delete the entire error line punched in the paper
tape. This is accomplished by simultaneously press-
ing and holding down both the feed and delete but-
tons (on either the 1052 or 1055).
4. Restart by keying the prefix and component-recog-
nition code for the reader containing the initial data
for this retransmitted line. (The home-component-
recognition special feature must be installed; other-
wise control is exercised by only the component as-
signment switch.)
5. Operate the home-reader-start button.
Note: Exercise care to insure that the correct button is
pressed after the last keystroke, not with this keystroke.
Correction Procedure for Line-Loop Operation
When transmitting to the line from a card reader and
an EOB code is sensed, the card moves to column 81,
and waits for an LRC answer. If the answer is positive,
the card is ejected to the stacker.
When the answer is negative, the card is recirculated
two additional times, if necessary. After the third at-
tempt, the card must be manually ejected by pressing
the eject button, 1056.( Otherwise a positive response
is transmitted when the reader is again polled, if the
resend button has been pressed. However, the reader
will not start because it is still awaiting an LRC an-
swer.) Then remove the error card from the stacker;
correct it, if necessary, and replace in the hopper in
front of cards not yet processed.
If a 1057 /1058 card punch is receiving data, the card
is punched and skips to column 81 upon receiving an
EOB code. If the LRC compare is negative, the card is
ejected and a new card is fed into the punch station.
The 1051 then transmits the LRC answer to the send-
ing system.
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