--- title: Re-Using Old XFINITY Security Hardware in a Real... description: A hands-on project reviving old Xfinity/Comcast security hardware — Visonic MCT-340 door sensors and a Centralite 3400-D keypad — by integrating them into a... canonical: https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Re-Using Old XFINITY Security Hardware in a Real Automation System | daily.dev og:description: A hands-on project reviving old Xfinity/Comcast security hardware — Visonic MCT-340 door sensors and a Centralite 3400-D keypad — by integrating them into a... og:url: https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde og:image: https://api.daily.dev/og/posts/Dc7kLPRdE.png og:image:alt: Re-Using Old XFINITY Security Hardware in a Real Automation System og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Re-Using Old XFINITY Security Hardware in a Real Automation System **[apalrd's adventures](https://daily.dev/sources/apalrd)** · 5 min read · 0 upvotes · 0 comments ## Summary A hands-on project reviving old Xfinity/Comcast security hardware — Visonic MCT-340 door sensors and a Centralite 3400-D keypad — by integrating them into a Zigbee2MQTT network. The sensors report door state, tamper status, temperature, and battery level. The keypad requires 4-digit codes and returns one of four arm/disarm modes, with response logic handled via a Node-Red flow integrated with Home Assistant. Node-Red flows are provided for both alarm keypad and general automation keypad use cases. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How does the Centralite 3400-D keypad work with Zigbee2MQTT — does it validate codes itself? The Centralite 3400-D does not validate keycodes itself. It transmits the full 4-digit code as soon as the 4th digit is pressed, along with one of four modes (disarm, arm all, arm day, arm night depending on which top button was pressed first). The Zigbee controller must validate the code and respond — if it does, the keypad beeps a success tone; if not, it beeps a failure tone and enforces a retry delay. _Teams building Zigbee alarm integrations track device quirks like these on daily.dev._ ### What batteries do the Visonic MCT-340 SMA and Centralite 3400-D use? The Visonic MCT-340 SMA door sensors use CR2032 batteries, while the Centralite 3400-D keypad uses two CR123A batteries. Both sizes are common in low-cost home automation hardware and are available in bulk packs. _Hobbyists wiring up Zigbee sensor networks find hardware-specific details like these on daily.dev._ ## Similar posts on daily.dev - [A Custom Zigbee Touch Keypad](https://daily.dev/posts/a-custom-zigbee-touch-keypad-po4d64rsy) · Hackaday · 0 upvotes · 0 comments - [A few Zigbee sensors and a light switch replaced my $250 Ring alarm system](https://daily.dev/posts/a-few-zigbee-sensors-and-a-light-switch-replaced-my-250-ring-alarm-system-nmyh1gxex) · XDA Developers · 0 upvotes · 0 comments - [Comcast gives its Wi-Fi motion detector a security makeover](https://daily.dev/posts/comcast-gives-its-wi-fi-motion-detector-a-security-makeover-obtsl2qpw) · The Register · 0 upvotes · 0 comments - [Home Hardware, Part 1: My Control4 Revenge Arc](https://daily.dev/posts/home-hardware-part-1-my-control4-revenge-arc-jsj4sfar8) · Reid Burke · 0 upvotes · 0 comments --- Tags: [#iot](https://daily.dev/tags/iot) [View this post on daily.dev](https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Re-Using Old XFINITY Security Hardware in a Real Automation System","url":"https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde"},"datePublished":"2026-08-11T08:55:31.243Z","dateModified":"2026-08-11T09:08:30.770Z","description":"A hands-on project reviving old Xfinity/Comcast security hardware — Visonic MCT-340 door sensors and a Centralite 3400-D keypad — by integrating them into a...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/93d67abc289c1f6d4a08151973ae8d08?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/93d67abc289c1f6d4a08151973ae8d08?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"apalrd's adventures","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"apalrd's adventures","logo":"https://media.daily.dev/image/upload/s--4zkx8dRj--/f_auto,q_auto/v1786438309/logos/apalrd?_a=BAMAMicg0","url":"https://daily.dev/sources/apalrd"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"iot","timeRequired":"PT5M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"apalrd's adventures","item":"https://daily.dev/sources/apalrd"},{"@type":"ListItem","position":3,"name":"Re-Using Old XFINITY Security Hardware in a Real Automation System"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/re-using-old-xfinity-security-hardware-in-a-real-automation-system-dc7klprde#faq","mainEntity":[{"@type":"Question","name":"How does the Centralite 3400-D keypad work with Zigbee2MQTT — does it validate codes itself?","acceptedAnswer":{"@type":"Answer","text":"The Centralite 3400-D does not validate keycodes itself. It transmits the full 4-digit code as soon as the 4th digit is pressed, along with one of four modes (disarm, arm all, arm day, arm night depending on which top button was pressed first). The Zigbee controller must validate the code and respond — if it does, the keypad beeps a success tone; if not, it beeps a failure tone and enforces a retry delay. Teams building Zigbee alarm integrations track device quirks like these on daily.dev."}},{"@type":"Question","name":"What batteries do the Visonic MCT-340 SMA and Centralite 3400-D use?","acceptedAnswer":{"@type":"Answer","text":"The Visonic MCT-340 SMA door sensors use CR2032 batteries, while the Centralite 3400-D keypad uses two CR123A batteries. Both sizes are common in low-cost home automation hardware and are available in bulk packs. Hobbyists wiring up Zigbee sensor networks find hardware-specific details like these on daily.dev."}}]} ```