IBM System/370 145 Manual page 145

cards as for SO-column cards. Stacker capacity is limited to 1500 cards
when this feature is installed, and intermixing 51- and SO-column cards
in the same input operation is Doi: supported.
THE 3525 CARD PUNCH
Either the 3525 Punch Adapter or the 3525 Read Punch Adapter must be
installed on the 3505 in order to attach a model of the 3525 Card Punch
to a system channel. These featUl:es can be field-installed. Models Pl,
P2, and P3 of the 3525 differ only in speed, and model changes can be
made in an installation. Any 352S model can be combined with either
3505 model.
The I/O commands used for the punch side of the 2540 without punch
feed read capability are a cotnpatible subset of those provided for the
3525. (The special punch feed reald command defined for the 2540 is not
used on the 3525, and it will caus;e a command reject error on the 3525.)
Additional commands for the 3525 siupport new features such as card
printing and Read Column. EliminatE!. Since a 3525 with the Card Read
feature installed can execute the same commands as the 3505 reader (all
features except optical mark readi.ng), the 3525 can be used as a second
or a backup card reader, if necessary ..
In the 3525, cards move from th.e hopper to a parallel read station
(dummy if the Card Read feature is not installed) and on to a parallel
punch station at which punch checking occurs. Then cards move to a
parallel print station (dummy if a card print feature is not installed),
after which they are stacked into one of two standard 1200~card-capacity
stackers under program control. Thus, reading, punching, and printing
can occur for each card during one pass, a facility not available on
other card units for System/370 models or on card units for System/360
Models 30 and up.
Card feeding on the 3525 is handled by picker knives as on a 2540
because this technique is required for parallel card reading operations
when an additional aligning station is not used. Parallel rather than
serial feeding is used in the 3525 to obtain the punch speeds available.
As
on a 3505, the entire card path in the 3525 can be exposed quickly if
a card jam occurs.
A new method of punch checking, which senses punch displacements, is
implemented in the 3525. Punch cbecking is achieved by monitoring the
actual motion of each punch. The
4~ontrol
unit compares the output from
the sensors at·tached to each punch to the data sent to be punched and
determines whether holes were actually punched and, if so, punched
correctly. Each card is also
chec]~ed
for correct position and skew to
ensure punch registration accuracy .•
A significant new recovery featltte of the 3525 is automatic punch
retry when combined read/punch opelrations are not being performed.
(Punch retry is effective during punch/print operations.) When a punch
error is detected, the control uni1: directs the error card to a 200-
card-capacity dedicated error stacker (stacker 3) located under the
covers of the 3525 and causes the output data in the buffer to be
repunched into the next card.
If
i~e retry is successful, the
correctly punched card is sent to 1:.he error stacker and the stacker 3
light is turned on to indicate to t:he operator that cards are in the
error stacker. (A correctly punchE~d card is placed in the error stacker
so that the customer engineer can c:ompare it with the incorrectly
punched card, which can
be
useiful in identifying the punch malfunction.)
Another card is then punched with t:he same data and stacked, after which
normal operations continue. These punch retry operations are controlled
entirely by the control unit. The.l~efore, punch retry is transparent to
the channel and the program and does not require operator intervention.
A Guide to the IBM system/310 Model. 145 135