Specifications for Tektronix Model 31

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, SN B052789, 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, 60Hz
Display Technology:  Gas Discharge Modules, Sperry SP-332(2-Digit) & SP-333(3-Digit) modules
Leading Zero Suppression (except at clear, display reads 0.000000000)
Logic Technology:  Custom AMI-made (to Tektronix Design) 13 device LSI Chip set
Chip set essentially functional equivalent of the Cintra 909 calculator
Part Numbers: (AMI Cxxxx/Tek 156-xxxx-00)
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
7400-Series TTL ICs for 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
Learn-mode program step storage of up to 8192 steps (see Memories)
Complete branching, with labeled jumps
One-level subroutine capability
Program-controlled load/store to/from Mag-Tape (Chaining)
Programmer implemented with 7400-Series TTL Logic
Peripherals:  Optional built-in 16-column alphanumeric thermal printer (Option 01)
Built-in magnetic cartridge tape drive
External device control via I/O interface (Similar to early GPIB)
Single ROM pack slot for ROM-based applications
Type 152 General Purpose BCD Interface
Type 154 RS-232C Serial Interface
Interface to Tektronix 4661 Digital Pen Plotter
Model 31/10 Graphics System
Model 31/53 Instrumentation System
  Provides programmatic reading of display from specific modified Tek TM500-Series instruments
  Special Tektronix TM503 TM500-Series Instrument Mainframe
  Tektronix Type 153 Instrument Interface Unit
  Specifically modified Tektronix DM501 Digital Multimeter Instrument
  Specifically modified Tektronix DC503 Counter/Timer Instrument
Calculator Performance:  Add/Subtract:  8ms
Multiply:  15-25ms
Square:  10-25ms
Divide, 1/x 15-20ms
Square Root 30-50ms
ex:  8-10ms
Loge(x):  8-10ms
Sin:  120-140ms
Cos:  140-160ms
Tan:  70-100ms

Previous Machine:  Texas Instruments SR-20
Next Machine:  Sharp PC-1001

Related Machines:  Cintra/Tektronix 909

Advertising:  Tektronix' TEKSCOPE Magazine Introduction of Model 21 and 31 Calculators [PDF, 16 Pages, 7.3MB]
Tek 21/31 New Product Flyer [97K]
Original Tek 31 8x10 Glossy Photo [36K]
"The first interactive graphic calculator." [86K]
Cover of Tek 31 Operator's Manual [41K]
Cover of Tek 31/53 Instrumentation System Brochure [67K]
"The first modular instrumentation calculator." [90K]
"Tektronix Programmable Calculators Catalog, 1973" [51K]

Patent:  US Patent 3,831,199A:  Common transport for magnetic tape cartridge or magnetic card cartridge

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