Error Procedures; Error At The 2795/2796 Data Entry Unit Or 1035 Badge R E A D E R; Error At The 2791 Area S T A T I O N; Length Check - IBM 2790 Manual

The 2790 Data Communication System involves a large num­
ber of operators. Therefore, operator errors as well as trans­
mission errors must be considered.
E R R O R A T T H E 2795/2796 D A T A E N T R Y U N IT OR
1035 B A D G E R E A D E R
The 2715 performs the following error checks on data
from the data entry units and the 1035 Badge Reader:
1. Digit 1 of a data entry contains a code (EBCDIC 0-3)
to designate the type of DEU. The 2795 transmits
a digit 0; the 2796 transmits a digit 1,2, or 3 depending
on the Monitor key position. The 2715 checks for a
transaction code and 12 data characters from a 2795,
and for a transaction code and 18 data characters
from a 2796.
2. At the user's option, the 2715 checks that a user-
provided check digit (0-9) compares with a digit read
in one of the first 15 positions of data. The user
exercises this option when preparing transaction-list
statements for data entry units and for the 1035
Badge Reader.
3. At the user's option, the 2715 counts all nonblank
characters in the data read from a DEU or 1035
Badge Reader and compares this count to a length
count supplied by the user in the transaction list
statements. The valid lengths that may be specified
are as follows:
2 7 9 5 - 2 through 12
2 7 9 6 - 8 through 18
1035-1 through 10
This length check is not performed by the 2715 if
the user specifies length equal to zero or if the length
check is omitted.
If a nonblank character count error is detected, the
2795/2796 operator is notified by the appearance of the
error indicator/reset button. The entry request lever
remains in a latched down position and the card or badge
is held. The operator resets the error and releases the card
or badge by pressing the error indicator/reset button. The
2715 discards the error data.
The 1035 operator is notified of a nonblank character
count error by the Repeat indicator lighting and the badge
remaining in the unit. The operator resets the error and
releases the badge by pressing the Clear switch. The 2715
discards the error data.
Note: The 2790 system reliability assumes that a non­
blank character length count check is performed by
either the 2715 or the user's System/360 problem
program. This check has been designed to provide for
detection of an error in which a blank character (hexa­
decimal 40) is substituted for a digit because a sensing
pinion in the DEU failed to deposit and hold in punches
0 through 9 of a card or badge column. Errors of this
type will be undetected unless the user performs the
nonblank character length count check either in the
2715 or in the application problem program.
The 2715 causes a Read-End command to be sent when
an error is recognized. The 2795/2796 operator is notified
by the error indicator/reset button snapping into view. The
entry request lever cannot be pressed for another operation
until the error indicator/reset button is pressed. The 2715
discards the data received in error from the data entry unit.
E R R O R A T T H E 2791 A R E A STA T IO N
At the user's option, the 2715 will check for two types of
errors at the 2791 Area Station. The user exercises this
option when preparing transaction list statements for the
2791 Area Stations.

Length Check

This check permits the user to instruct the 2715 to check
the length of a data entry from a 2791 device against a
user-provided value. The 2715 length count includes only
nonblank characters. The valid lengths that may be speci­
fied are as follows:
Card R ead er-1 through 81
Manual Entry—1 through 7
Digital Device Read-In—1 through 11
Badge Reader—1 through 11
This length check is not performed by the 2715 when
length equal to zero is specified or if the length check is
omitted.
Note: A manual entry from the 2791 always sends six
data characters, some of which can be blank. The blank
characters will be excluded from the customer-specified
length count.
When a length check is specified, the user should also
specify the error guidance lamp to be lit if the actual data-
entry length is not equal to the length supplied in the
transaction-list statement.

Error Procedures

Error Procedures 57