The Museum of HP Calculators


HP-42S Features

Features in optional ROMs are listed as Option.
Features in HP mag card or tape Application Pacs are listed as +.
Other software is not included.

Display and Keyboard HP-42S
Display type LCD
Display format 2 Line
FIXed number format Yes
SCIentific number format Yes
ENGineering number format Yes
STanDard / ALL number format Yes
Alpha messages and prompts Yes
Softkeys labeled by mag. card or overlay -
Softkeys labeled by display menus Yes
Softkeys with neither labeling system -
Status annunciators Yes
Redefinable keyboard Yes
   
Logic HP-42S
Logic system RPN
Stack levels 4
Last x Yes
Undo -
Precedence -
Parentheses -
Storage Addition (STO +) Yes
Storage Arithmetic (STO +, -, ×, ÷) Yes
Storage Exponentiation (STO ^) -
Recall Arithmetic Yes
Named variables Yes*
Multiple data types Yes*
Directories -
   
Math HP-42S
+, -, ×, ÷ Yes 
1/x Yes
sq. root Yes
x2 Yes
LOG x Yes
10x Yes
LN x Yes
ex Yes
yx Yes
pi Yes
% Yes
% change Yes
INTeger truncation and ABSolute value Yes
Trigonometric functions (SIN, COS etc.) Yes
Hyperbolic trig. (SINH, COSH etc.) Yes
# of trig. modes (degrees, radians, grads) 3
   
Advanced Math HP-42S
Solver / root finder Yes
Numeric integration Yes
Complex numbers Yes
Matrix operations Yes
Matrix writer -
Equation writer -
Symbolic operations -
Fractions -
Plotting and graphics (display) Yes
Plotting and graphics (printer / plotter) Option
   
Statistical HP-42S
Mean, standard deviation (# of variables) 2
Summation of n, x, x2 Yes
Summation of n, x, x2, y Yes
Summation of n, x, x2, y, xy Yes
Summation of n, x, x2, y, y2, xy Yes*
Summation of lists -
Random number generator Yes
Linear regression, estimate  Yes
Curve fitting Yes
Correlation coefficient Yes
Normal distribution -
Factorial Yes
Gamma Yes
Combinations and permutations Yes
   
Scientific and Time

HP-42S

Polar / rectangular conversions Yes
Base conversions (2, 8, 10, 16) Yes
Arithmetic in bases 2, 8 and 16 Yes
Bit operations (AND, OR, XOR, ...) Yes
Selectable word size (1-64 bits) -
Selectable complement mode (1's, 2's, unsigned) -
Decimal hrs / hrs.min.sec. conversions Yes
Hrs.min.sec arithmetic Yes
Time of day clock -
Timer -
Dynamic calculations (timer × rate) -
Alarms -
   
Unit Conversions

HP-42S

Centimeters / inches -
Millimeters / inches -
Meters / feet -
Kilograms / pounds (mass) -
Newtons / pounds (force) -
British thermal units / joules -
Liters / gallons -
° Celsius / ° Fahrenheit -
Other -
User-defined units -
   
Time Value of Money HP-42S
Number of payments (n) -
Interest rate (i) -
Present Value (PV) -
Payment (PMT) -
Future Value (FV) -
   
Cash Flow Analysis HP-42S
Net present value (NPV) -
Internal rate of return (IRR) -
   
Amortization HP-42S
Accumulated Interest (ACC INT) -
Balance (BAL) -
   
Depreciation HP-42S
Straight line (SL) -
Sum of the years digits (SOYD) -
Declining balance (DB) -
   
Bonds and calendar functions HP-42S
Bond price -
Bond yield -
Date arithmetic / calendar functions -
   
Memory and Programming HP-42S
Programming language(s) RPN
RAM / Max # of variables or addressable registers 7200 bytes /
895 registers
Max # of program steps 7200*
RAM / Max vars or regs with full optional RAM -
Max # of prog steps with full optional RAM -
Merged program steps 

Yes

Manual register / program memory allocation  Yes
Automatic register / program memory allocation

-

Overlapped register and program memory -
Continuous memory

Yes

Flags 100
Conditional tests 12
Subroutine levels 8
Indexed looping (increment by +/- 1, end at 0) Yes
Indexed looping (choice of increment and end) Yes
Multiple index / loop registers Yes
Line number addressing -
Branching by relative line number -
Global program label addressing Yes
Local program label addressing Yes
Indirect / computed addressing and control Yes
Multiple indirection registers Yes
Pause Yes
Alpha messages and prompts in programs Yes
Alpha program listings Yes
Alpha string manipulation Yes
Program step insert / delete Yes
   
I/O and Expansion Features HP-42S
ROM modules -
RAM modules or expansion option -
General expansion slots / connector -
Magnetic card reader/writer -
Tape drive -
Disk drive -
Upgradeable firmware -
Optical wand -
Serial port -
Infrared input -
Infrared output Yes
Printer Option
Networking -
Other -
   
General HP-42S
Sounds Yes
Self test Yes
Hard case (in addition to soft case) -
Additional Features -
Batteries 3 SR 44
Length (inches) 5.85"
Width 3.15"
Height 0.6"
Weight (oz or lbs) 5 oz
Year of introduction 1988

Features in optional ROMs are listed as Option.
Features in HP mag card or tape Application Pacs are listed as +.
Other software is not included.

Unlim means limited only by available memory.

HP-42S notes:
  • Named variables AND numbered registers.
  • Manual presented basic Time Value of Money formula as an example of using the Solver.
  • Besides n, x, x2, y, y2, xy, the calculator also summed: ln x, (ln x)^2, ln y, (ln y)^2, ln x × ln y, x ln y, and y ln x
  • Data types were real, complex, string and alpha. Any type could be stored in the stack or in a variable, but only single numbers could be stored in numeric registers and you had to convert all registers to complex to store a complex number in any register.
  • Maximum number of program lines assumes no registers and only single byte instructions.
  • To start the self test, with the calculator on, press and hold the LOG key and press the ON/EXIT key. Pressing the + key will step through a series of tests (including printing a copyright) until you see KBD. Then you must press each key from the upper left from left to right and then down until you see KBD OK. Pressing + will show OK-42S-E. If there is a problem, you will see a FAIL message. To exit the test, at any point, press and hold the square root key and then press the ON/EXIT key. Instead of stepping through the general tests, you can start some specific self tests after pressing LOG+ON/EXIT by pressing
    • SUM+: Speed
    • 1/x: Beep
    • square root: DISP
    • LOG :ROM
    • LN: DRAM
    • XEQ: URAM
    • RCL: ESD (electro-static discharge test?)
    • STO: KBD
    • Roll down: Displays the OK message
  • A continuous test (minus the keyboard test) can be started by holding 1/x and pressing ON/EXIT. Exit this test in the same way as the individual test.

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