Manufacturer: 
Tektronix, Inc. 
Model Number: 
31 
Serial Number: 
Four Units in Museum 

#1: B052789 

#2: B031961 

#3: BB09 

#4: No Serial Number  Prototype 
Introduction: 
August 2, 1973 
Date of Manufacture: 
Exhibited Calculator, Late 1973 
Manufactured In: 
USA, Beaverton, Oregon 
Original Price: 
$2,850 Base Price at Introduction 

$700 Option 01 Printer 
Weight: 
32 Pounds 
Size: 
8 3/4" Wide, 15 1/4" Deep, 6" High 
Power Requirement: 
100 Watts Max, Jumper Selectable 120/240V AC 
Display Technology: 
Sperry DC Plasma SP332 & SP333 modules 

Leading Zero Suppression (except at clear) 
Logic Technology: 
AMImade (to Tektronix Custom Design) LSI Chipset 

Chipset essentially functional equivalent of the Cintra 909 calculator 

Part Numbers: (AMI Cxxxx/Tek 156xxxx00) 

C8684/0235, C8685/0231, C8686/0232, C8687/0233,


C8688/0234, C1836/0239, C1837/0240, C1838/0242,


C1839/0237, 2xC1840/0238, 2xC1841/0236, C1842/0243,


C1843/0241


7400Series TTL ICs for programmer and miscellaneous logic


Intel 2102/Signetics 2602 1Kx1 static RAM for program/memory storage


Two Main Circuit Boards (calculator and programmer)


Memory board(s) piggyback on programmer board

Digits of Capacity: 
10 mantissa, 2 exponent, both with sign


12 digits calculated, 2 guard digits not displayed

Decimal Modes: 
Floating and Normalized Scientific Notation

Arithmetic Logic: 
Full Algebraic Logic w/heirarchy and parenthesis

Math Functions: 
Comprehensive, see exhibit for details 
Constant: 
No 
Memories: 
Depends on memory configuration: 

Standard: 512 Program Steps, 64 Memory Registers


Option 02: 1024 Program Steps, 128 Memory Registers


Option 03: 1536 Program Steps, 192 Memory Registers


Option 04: 2048 Program Steps, 256 Memory Registers


Option 05: 2048 Program Steps, 640 Memory Registers


Option 06: 3584 Program Steps, 448 Memory Registers


Option 07: 5120 Program Steps, 256 Memory Registers


Option 08: 2048 Program Steps, 1000 Memory Registers


Option 09: 5120 Program Steps, 640 Memory Registers


Option 10: 8192 Program Steps, 256 Memory Registers


Serial #B031961 Equipped with Option 02


Serial #B057289 Equipped with Option 09

Programmable: 
Yes, Extensive Features 

Learnmode program step storage of up to 8192 steps (see Memories)


Complete branching, with labeled jumps


Onelevel subroutine capability


Programcontrolled load/store to/from MagTape (Chaining)

Peripherals: 
Optional Builtin 16column thermal printer (Option 01)


Builtin magnetic cartridge tape drive


External devices via I/O interface (early GPIB/IEEE 488like)


Single ROM pack slot for ROMbased applications


Model 152 General Purpose BCD Interface


Model 153 Tektronix Instrument Interface


Model 154 RS232C Interface


Model 31/10 Graphics System


Model 31/53 Instrumentation System


Interface to Tektronix 4661 Digital Pen Plotter

Performance: 
Add/Subtract: 8ms


Multiply: 1525ms


Square: 1025ms


Divide, 1/x 1520ms


Square Root 3050ms


e^{x}: 810ms


Log_{e}(x): 810ms


Sin: 120140ms


Cos: 140160ms


Tan: 70100ms
