IBM 2790, Manual

Page: 13 / 88

Transaction Header (8 Bytes)
1 2 3 4
5 6 7 8
Transaction
Length
Transaction
List Number
*
Area
Station
Address
Device
Address
Tens
of
Hours
Units
of
Hours
Tens
of
Minutes
Units
of
Minutes
Vr ...... mms
J
Binary Time-of-Day (EBCDIC)
* Upper left-hand rotary switch references a transaction
from the user's transaction table. The transaction list
number from the table is placed in byte 2 of the header.
Data Entry (18 EBCDIC Digits)
Digit
Digit
1 2 3 4 5
6
7 8 9
Monitor
Upper
------------------ 1 i------------------
Card or Badge Columns
Key
Right
71 72
73 74
75 76 77
( 1 ,2 ,or 3)
Rotary
Switch
13 14 15 16 17 18
19
10 11 12 13 14
15 16
17
18
Lower
Lower
■
Rocker Thumbwheel Switches
78 79 80
Left Right
20 21 22
Rotary
Switch Rotary
Switch
1 2 3 4
Figure 7. 2796 Data Entry as Assembled in the 2715 TCU
2796 Data Entry
A 2796 data entry as assembled in the 2715 TCU consists
of 18 digits of data plus transaction-header information (see
Figure 7):
Digit 1—Monitor key setting and type of DEU.
Digit 2—Setting of upper right-hand rotary switch.
Digits 3 through 12—Contents of card or badge. Blanks
are transmitted for these positions if a card or badge
is not entered as part of the data entry.
Digit 13—Setting of lower left-hand rotary switch.
Digit 14—Setting of lower right-hand rotary switch.
Digit 15 through 18-Setting of four rocker-thumbwheel
switches.
Note: Such information as device address, area station
address, and upper left-hand rotary switch setting are
also transmitted to the system controller. The system
controller constructs a transaction header from this
information and prefixes it to the transaction containing
the data entry.
D A T A E N T R Y U N IT T R A N S A C T IO N S E L E C T IO N
The combination of the area station’s address, the data
entry unit’s address, and the setting of the left-hand (upper
left-hand for 2796) rotary switch selects the proper trans­
action list from the user’s transaction-list table. The trans­
action list provides the controls to process the data entry.
All 2795’s assigned to a given AS must use the same
transaction list for corresponding rotary-switch settings
(transaction code). All 2796’s assigned to a given AS must
Data Entry Units 13