---
title: "ZT21000"
id: 20325
type: "product"
slug: "zt21000"
url: "http://localhost/product/zt21000/"
markdown_url: "http://localhost/product/zt21000.md"
published_at: "2019-11-29T22:46:17+00:00"
modified_at: "2026-03-22T13:23:10+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "Expansion unit for ZX81/TS 1000. Promised 64-key auto-repeat big keyboard, 15 colors, 32K RAM onboard, 3 kinds of sound, 33 new BASIC commands, multiple statement and input lines, 6 video pages, high resolution (256x192 pixels) and animation capabilities, user-definable characters and character sets and up to 9 user-definable functions. RS232 and parallel interfaces, two Atari-compatible…"
category:
  - name: "Miscellaneous"
    slug: "misc"
    taxonomy: "category"
    url: "http://localhost/category/hardware/misc/"
post_tag:
  - name: "Proprietary International"
    slug: "proprietary-international"
    taxonomy: "post_tag"
    url: "http://localhost/tag/proprietary-international/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
  - name: "ZX81"
    slug: "zx81"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx81/"
model:
  - name: "Sinclair ZX81"
    slug: "zx81"
    taxonomy: "model"
    url: "http://localhost/model/zx81/"
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
genre:
  - name: "Hardware"
    slug: "hardware"
    taxonomy: "genre"
    url: "http://localhost/type/hardware/"
  - name: "Miscellaneous hardware"
    slug: "miscellaneous-hardware"
    taxonomy: "genre"
    url: "http://localhost/type/miscellaneous-hardware/"
company:
  id: 20336
  title: "Proprietary International"
  type: "company"
  url: "http://localhost/company/proprietary-international/"
price: 200
rarity: "Uncommon"
articles:
  - article:
      id: 19389
      title: "Proprietary International Announces ZT21000"
      type: "article"
      url: "http://localhost/article/proprietary-international-announces-zt21000/"
  - article:
      id: 19429
      title: "Vendor Report"
      type: "article"
      url: "http://localhost/article/vendor-report/"
  - article:
      id: 19427
      title: "Wanted: Assembly Language Programmers"
      type: "article"
      url: "http://localhost/article/wanted-assembly-language-programmers/"
companies_products:
  - id: 20336
    title: "Proprietary International"
    type: "company"
    url: "http://localhost/company/proprietary-international/"
---

# ZT21000

Expansion unit for ZX81/TS 1000. Promised 64-key auto-repeat big keyboard, 15 colors, 32K RAM onboard, 3 kinds of sound, 33 new BASIC commands, multiple statement and input lines, 6 video pages, high resolution (256×192 pixels) and animation capabilities, user-definable characters and character sets and up to 9 user-definable functions. RS232 and parallel interfaces, two Atari-compatible joystick ports and a PROM cartridge port. Saves and loads at 1.5 Kbaud.