HP 71B

The HP 71B is a pocket computer and scientific calculator produced by Hewlett Packard.

HP 71B

Other names	HP 44A (during development)
Type	Pocket computer, scientific calculator
Introduced	1983
Discontinued	1989
Predecessor	HP 75
Successor	HP 94, HP 95LX
Cost	550 USD
Calculator
Entry mode	Algebraic
Display type	Dot-matrix LCD
CPU
Processor	HP Saturn 1LF2 or HP Saturn 1LK7
Frequency	640kHz
Programming
Interfaces
Ports	4x ROM/RAM slots, 1x card reader/ROM/RAM header, 1x HP-IL/ barcode reader module slots
Other
Power supply	4x AAA battery or 8VAC power supply

Internal design

Internally, the HP 71B is divided up into two separate boards, earlier models use a ribbon cable to connect the boards, while later models use a zebra strip. The upper board contains the Saturn microprocessor, keyboard, and display. The lower board contains the power supply hardware, ROM, RAM, and expansion slots.

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  Upper board (1983)

• 

  Lower board (1983)

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  Upper board (1987)

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  Lower board (1987)

Programming

By default, the 71B only supports programming in the BASIC language. Additional keywords can be added to BASIC through the use of an expansion ROM module.

Support for Forth can be added through the use of the Forth/Assembler expansion ROM module.

Sample BASIC program

This is a sample program which will play a tone on the buzzer for 0.5 seconds, then increase the frequency non linearly and repeat, while displaying the frequency being played.

10 X=10
20 Y=20
30 PRINT X
40 BEEP X
50 X=X+Y
60 Y=Y+5
70 GOTO 30

Accessories

Front expansion slots

• HP 4K RAM module (HP 82420A)
• CMT RAM modules
• CMT EPROM module
• Various ROM modules by HP and others

Rear expansion slot

• HP-IL interface (HP 82401A)
• Dual HP-IL interface (HP 82402A)
• Zenwand-71 barcode reader

Card reader slot

• Magnetic card reader (HP 82400A)
• FRAM71
• HHP 71RAM/EPROM modules
• CMT RAM/EPROM modules

External resources

• HP 71B Compendium (PDF) - A thorough listing of accessories and software available for the HP 71B