---
title: Texas Instruments TI-55-II
categories:
- Computers
types:
- Pocket
origins:
- U.S.A.
years:
- '1981'
params:
  name: TI-55-II
  company: /companies/texas-instruments
  company_name: Texas Instruments
  specs:
  - label: NAME
    value: TI-55-II
  - label: MANUFACTURER
    value: Texas Instruments
  - label: TYPE
    value: Pocket
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: September 1981
  - label: KEYBOARD
    value: 45 keys
  - label: RAM
    value: 56 steps - 7 memories
  - label: TEXT MODES
    value: 10 digits LCD display
  - label: POWER SUPPLY
    value: Lithium batteries
  - label: PRICE
    value: $50
  tabs:
  - adverts
  adverts:
  - title: U.S. ADVERT(1982)
    subtitle: ''
    text: The calculator was sold with a very helpful manual (Calculator Decision-Making Sourcebook) giving step- by-step examples for the best techniques used for solving mathematical, statistical and scientific problems, as well as programming tips.
    image: null
  comments:
  - author: Bill Plante
    date: Saturday 3rd November 2012
    text: For over 18 years in engineering, my TI-55-II was my constant companion$ after 29 years, it''s still on my desktop. Just did a search of my library. I seem to have lost the Quick Reference Guide, but I''ve still got the green "SourceBook" with all the program keying instructions.
  - author: Bill Plante (USA)
    date: Saturday 3rd November 2012
    text: WOW! Just saw your piece on the TI-55-II. Bought mine when they first came out (not the Brazil model). After all these years, it''s the one I use almost every day. It''s a little scuffed, but it works flawlessly and dependably! I change the batteries every 2-3 years. I even still have the case!
  - author: Keith (US)
    date: Sunday 27th June 2010
    text: |-
      I bought one of these when my TI-55 died on me. The quality of this model was abysmal. The buttons were unreliable. It usually took multiple button presses to get them to work and when they did work, many times you would get multiple entries.

      About 13 years later I worked at TI and was talking to one of the engineers when the subject of the TI-55-II came up. When I told him I had owned one he asked me if it was any good. I told him that the buttons sucked. He sort of chuckled to himself. I guess they realized that it sucked as well.
  oc_id: 597
  source:
    url: https://web.archive.org/web/20230604171839/http://www.old-computers.com/museum/computer.asp?c=597
    date: '2023-06-04'
---

The TI-55 was one of the first programmable calculator which keeps programs and data in memory, even when it was turned off.

112 pre-programmed functions, including statisticals.