---
title: "Phone Line Filter"
type: "article"
slug: "phone-line-filter-3"
url: "http://localhost/article/phone-line-filter-3/"
markdown_url: "http://localhost/article/phone-line-filter-3.md"
published_at: "2026-03-13T14:09:27+00:00"
modified_at: "2026-03-13T14:09:28+00:00"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "Describes building a simple phone line filter using a 2µF capacitor and 2.75K resistor to reduce modem noise at 2400 baud. Includes a circuit diagram and construction guidance for the hardware project."
category:
  - name: "The RAMTOP"
    slug: "the-ramtop"
    taxonomy: "category"
    url: "http://localhost/category/periodicals/the-ramtop/"
post_tag:
  - name: "Hardware project"
    slug: "hardware-project"
    taxonomy: "post_tag"
    url: "http://localhost/tag/hardware-project/"
indiv:
  - name: "James DuPuy"
    slug: "james-dupuy"
    taxonomy: "indiv"
    url: "http://localhost/indiv/james-dupuy/"
publication_r:
  id: 39272
  title: "The RAMTOP"
  type: "periodical"
  url: "http://localhost/periodical/the-ramtop/"
authors_r:
  - name: "James DuPuy"
    slug: "james-dupuy"
    taxonomy: "indiv"
    url: "http://localhost/indiv/james-dupuy/"
issues_articles:
  - id: 50261
    title: "The RAMTOP 1st Qtr 1990"
    type: "issue"
    url: "http://localhost/issue/the-ramtop-1st-qtr-1990/"
pages: "3"
pubdate: "1st Qtr 1990"
archive_link: false
---

# Phone Line Filter

Describes building a simple phone line filter using a 2µF capacitor and 2.75K resistor to reduce modem noise at 2400 baud. Includes a circuit diagram and construction guidance for the hardware project.