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File Number S360 -03
Form A21-9033-1
Systems Reference Library
IBM 2540 CompoI1lent Description
1
and Operating Procedures
This publication explains the operating principles,
procedures, and controls of the IBM 2540 Card
Read Punch. Special features for the 2540 are
also discussed.
Refer to the SRL publication, IBM 2821 Control
Unit, Form A24-3312, for information concerning
the commands, status and sense indicators, and
other programming considerations that affect the
2540.
This publication is a major revision, and obsoletes the previous
edition, Form A21-9033-0. R~:start procedures have been revised
in several places, and other minor changes have been made
throughout the manual.
Copies of this and other IBM publications can be obtained through IBM Branch Offices.
Address comments concerning the content of this publication to: IBM Corporation,
Product Publications, Dept. 245, Rochester, Minn. 55901
C International Business Machines Corporation 1965
CONTENTS
5 IBM 2540 CARD READ PUNCH
5 Introduction
5 Operating Principles
5 Data-Mode 1
5 Reading
5 Punching
5 Stacker Selection
8 Special Features
8 Data-Mode 2
8 Punch Feed Read
9 51-Column Interchangeable Read Feed
9 Operator Controls
9 Reader Controls
10 Punch Controls
11 Common Indicator Lights
11 Operating and Restart Procedures
11 Initial Start
11 Restarts from Error Conditions
11 Jam Removal
IBM 2540 Card Read Punch
IBM 2540 CARD READ PUNCH
INTRODUCTION punches in the card and develop a hole count for each
column. On the third cycle, the card passes through
The IBM 2540 Card Read Punch is an input~output the read station to the pte-stacker station. Data read
device for IBM System/360 Models 30 and higher. from the card during the third cycle enters the read
Connection of the 2540 to a System/360 processing buffer in the 2821, from where it will be passed to the
unit is made through an IBM 2821 Control Unit, channel in response to the next read instruction.
Model 1, 4, or 5, attached to a multiplexor or Also during the third cycle, a second hole count
selector channel. All data and control signals trans- is developed by the read brushes for each column and
ferred between the processing unit and the 2540 pass compared to the hole count from the read-check sta-
through the 2821; buffers in the 2821 permit the tion. Disagreement between the two counts results
transfer of data independent of the reading and punch- in a read-check.
ing speed of the 2540.
The 2540 has separate read and punch feeds, with
maximum reading speed of 1000 cards per minute Punching
and maximum punching speed of 300 cards per min-
ute. The punch hopper holds approximately 1350 The punch operation requires four machine cycles.
cards; the read hopper and file-feed magazine hold During the first cycle, the card leaves the hopper
approximately 3100 cards. and moves to the blank station (Figure 2). During
The five radial stackers of the 2540 are so con- the second cycle, the card moves past the blank
trolled that three stackers serve each feed: stackers station to the punch station.
R1 and R2, at the right end of the stacker group, can Data from the punch buffer in the 2821 is punched
receive cards from the read feed only; stackers P1 into the card during the third cycle as the card moves
and P2, the leftmost stackers, can receive cards row-by-row through the punch station, and a hole
from the punch feed only; and the center stacker, count of the data being punched is developed and
RP3, can receive cards from both feeds. RP3 should stored for each column. During the fourth cycle,
not be used for both the reader and the punch at the the card passes through the punch-check station,
same time. Each stacker holds approximately 1350 where the punch-check brushes read the card, and
cards; cards can be removed from any stacker with- develop a second hole count for each column, com-
out interrupting operation of the 2540. paring it to the hole count from the punch station.
After punch checking, the card passes into the
stacker area.
OPERATING PRINCIPLES
Data-Mode 1 Stacker Selection
The 2540, as well as all System/360 configurations, Read-stacker selection on the 2540 can be specified
uses the EBCDI code (Extended Binary Codc~d Decimal with the card-read instruction, or selection can be
Interchange code) for all operations in data-mode 1 delayed until the program can evaluate the informa-
(Figure 1). Information processed in data-mode 1 is tion read from the card and determine the appropri-
checked for validity according to the rule, "Any com- ate stacker. There is no time limit for specifying
bination of punches in a single card column is valid the stacker selection, except that the select command
if it contains no more than one punch in rows 1-7. I' must be given before, or with, the next Read com-
mand.
Reading
The 2540 read operation requires three machine NOTE: If the 2540 Compatibility special feature
cycles. During the first cycle, the card moves is installed on the 2821, and the 2540 is operating
from the hopper to the read-check station (Figure 2). in 2540 compatibility mode, stacker selection can-
During the second cycle, the card passes through the not be specified with the read instruction, but must
read-check station to the read station. During the - be specified within six milliseconds after data from
second cycle, the read-check brushes read the the card is passed to the channel.
5
01 .Bit POlitionl Bit Positions
10 11
0,1 0,1
Bit Positionl Bit Positionl
00 I 01 110 111 2,3, 00 01 1O 00 01 10 2,3
" " ...--
0000
CD @ G)
OS
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