---
title: "I/O Expansion Port"
id: 11665
type: "product"
slug: "8-port-io"
url: "http://localhost/product/8-port-io/"
markdown_url: "http://localhost/product/8-port-io.md"
published_at: "2019-11-30T01:31:50+00:00"
modified_at: "2026-03-22T13:14:00+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2019/11/micro-development-io.png"
excerpt: "Provides a buffered bus that decodes the address lines and inhibits the internal 1K RAM (and external 16K RAM) when I/O is selected. Up to 8 byte-wide ports. Connects to the ZX-81 via a custom cable."
category:
  - name: "Interfacing"
    slug: "interfacing"
    taxonomy: "category"
    url: "http://localhost/category/hardware/interfacing/"
post_tag:
  - name: "Gladstone Electronics"
    slug: "gladstone-electronics"
    taxonomy: "post_tag"
    url: "http://localhost/tag/gladstone-electronics/"
  - name: "Micro Developments"
    slug: "micro-developments"
    taxonomy: "post_tag"
    url: "http://localhost/tag/micro-developments/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
model:
  - 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: "Interfacing"
    slug: "interfacing"
    taxonomy: "genre"
    url: "http://localhost/type/interfacing/"
company:
  id: 11099
  title: "Micro Developments"
  type: "company"
  url: "http://localhost/company/micro-developments/"
price: 89
date: 1983
rarity: "Uncommon"
product_reviews:
  - id: 8614
    title: "Input/Output Board lets you add on peripherals"
    type: "article"
    url: "http://localhost/article/input-output-board-lets-you-add-on-peripherals/"
articles:
  - article:
      id: 8614
      title: "Input/Output Board lets you add on peripherals"
      type: "article"
      url: "http://localhost/article/input-output-board-lets-you-add-on-peripherals/"
adverts:
  - publication:
      - id: 26649
        title: "SYNC v3 n3"
        type: "issue"
        url: "http://localhost/issue/sync-v3-n3/"
    advert_page: "86"
companies_products:
  - id: 10902
    title: "Gladstone Electronics"
    type: "company"
    url: "http://localhost/company/gladstone-electronics/"
  - id: 11099
    title: "Micro Developments"
    type: "company"
    url: "http://localhost/company/micro-developments/"
---

# I/O Expansion Port

Provides a buffered bus that decodes the address lines and inhibits the internal 1K RAM (and external 16K RAM) when I/O is selected. Up to 8 byte-wide ports. Connects to the ZX-81 via a custom cable.