RCA 301 Programmer's Reference Manual page 30

When the Write-Tally switch is in the Write position, every card extracted is prewritten. When the Write-Tally
switch is in the Tally position and the device is in "Remote", normal count-down will be performed.
The Tally quantity is always recorded with the ten (10) least significant bits all 0's. The five (5) high order
bits are recorded in accordance with the switch setting; therefore, the number is 1,024 times N, where N's the number
from 0-31, set into the five (5) binary switches. The maximum number that can be recorded is 31 x 1,024, or 31,744.
All Tally operations occur before the card reaches the Read/Write Head on the first pass of the card. Therefore,
a card circulating on the capstan cannot be initialized by setting the Write-Tally switch to Write; the switch must
be set before the card reaches the capstan.
The Controlling switches are as follows:
Up - 1
Down = 0
Note: When the "Write-Tally" switch is in the "Write" position, it will cause the amount specified to
be written on the card while in either the Local or Remote Mode. Care must be exercised when
using this feature in the Remote Mode to avoid overwriting a valid existing Tally count.
11-14
16
o o o o o
Write
O
Tally