Texas Instruments SR‑56


Brand: Texas Instruments
Model: SR-51
Type: Programmable scientific calculator
Picture: SR-56
Batteries: Battery pack
Lifetime: Introduced: 1976
Terminated: 1977
Notes: This is a scientific calculator, successor to (or brother of) the TI SR-52. Unlike the TI SR-52 this one doesn't have a magnetic card reader.

The TI SR-56 was followed shortly by the TI 57 which is similar in many ways but can not be connected to the PC-100 printer.

Also present are some statistical functions.

This series of programmable calculators (TI SR-52, TI SR-56, TI 57, TI 58, TI 58 C, TI 59) really set the tone of most programmable scientific calculators to follow. But they also clearly borrow from the fabulous HP calculators that came before them.

This one in my collection doesn't work; when switched on the display shows random garbage (battery/adapter abuse?). I usually do not add defective calculators to my collection but in this case I made an exception. I am however still looking for a working version, so if you should encounter one please let me know.


This calculator can be mounted on top of an extension module, which I have never actually seen myself. This module connects via a row of contacts in the calculator's battery compartment. Available are the printers PC-100A and the PC-100C.

There is also a power adapter.