31
The Tektronix 21 and Tektronix 31 are programmable desktop calculators. The 31 features program branching and a complete set of transcendental functions.
They are built around a custom LSI chip set.
Several interfaces were available:
- Model 152 General Purpose BCD Interface
- Model 153 Tektronix Instrument Interface
- Model 154 RS-232C Interface
These connect to the calculator through a 50-pin card-edge bus interface supporting DMA access at up to 125 kbyte/s. The bus uses open-collector TTL drivers and can be daisy-chained through multiple peripherals (which all have two matching bus connectors for this purpose). It must be terminated at the last unit.
The 31/10 Graphic Calculator System was a bundle of a model 31 with a 4010-1 graphics terminal, interface and software collection.
Manuals
- Tektronix 21 and 31 Preliminary Manual (PDF, needs OCR)
- Tektronix 21 and 31 calculators interfacing information
Links
- Tek 21 / Tek 31 @ oldcalculatormuseum.com / Spec sheet / blog post
- Tektronix 31 Programmable Desktop Calculator running a counter program from tape @ YouTube
- Tek 31 picture / back side
