HP 82104A Owner's Handbook Manual page 26

24 Card Reader Operations
Using fotax). Like [worax], this function uses a number in the X-register
to control the card operation. uses the number in X to determine
where to place the information read from the data cards.
Here is the procedure for using [RoTAx).
1.
Ensure that the calculator is not in PRGM mode.
2. Using the following format, key a data read control number into
4.
the X-register.
bbb.eee
where: bbb is the beginning data register address;
eee is the ending data register address.
Refer to (wotax] for more information about bbb.eee (page 22).
With the control number in the X-register, execute [rotax). In a
program, simply key the control number into the X-register (as a
line in the program) and follow it with the function.
The HP-41C will prompt you to insert a card with the standard
prompt.
RDY kk OF nn
You can construct ALPHA prompts in your programs that appear
in the display instead of the standard prompt. Here is an example:
01 LBL'DGF
02TDATA CARD
03 AVIEW
04 RDTAX
The display will show DATA CARD instead of the standard prompt when
the is executed. After the first track of the card is read, all
subsequent tracks are prompted with the standard prompt.
5.
Insert the data card into the card reader. The calculator now uses
the control number to determine where to place the information on
the cards. Remember that during a multi-track read session, you
can insert the cards in any order. The HP-41C automatically keeps
track of the relative order of the tracks and the data on them.
Regardless of the reading order, the calculator always prompts
you for the lowest numbered track not yet read.