Texas Instruments TI-53

Description

Brand: Texas Instruments
Model: TI-53
Type: Programmable scientific calculator
Picture: TI-56
Batteries: LR44 x 2
Lifetime: Introduced: 1985
Terminated: unknown
Notes: The type designation of this calculator seems to refer to the earlier models TI 57, TI 58, TI 58 C and TI 59.

The TI-53 is a keystroke programmable calculator with an 8-digit slightly slanteed LCD. It can store a sequence of 31 programming steps. The calculator has constant memory for its single memory and its programming.

Programming wise does not provide any methods for conditional flow control but programs can be single stepped using the SST key.

The R/S can be programmed to stop the sequence, press it again to continue. End a sequence using R/S followed by the function to jump back to the first symbol of the sequence.

It is necessary to end a sequence by including the R/S key.

A Very Simple Programming Example:
Multiply any number by 42:

First, use RST to go to the start of the sequence, then press LRN to enter programming mode and enter the sequence:

× 4 2 = R/S RST

Press LRN again to leave programming mode and use RST to jump to the start, and enter any number followed by R/S to multiply it by 42.
Note that this is not the first TI-53 programmable calculator by Texas Instruments. The first one is from 1978. It’s also not the last one, according to Datamath there is a second version of this model from 1986 (see link below).

I quite like its clear layout and looks, although it seems to be missing a row of keys.

More inforation is available on this Datamath page (link validated 2026-09-15).