{"product_id":"4-port-av-control-expander-serial-relay-ethernet","title":"4-Port AV Control Expander — Serial, Relay \u0026 Ethernet","description":"\u003cp\u003e\u003cstrong\u003eSome remote locations need more than a single control drop — but not a full processor.\u003c\/strong\u003e The KanexPro CR-EXPAND4 bridges the gap with four extended serial ports and four relay outputs in one compact Ethernet-connected box. The first two extended ports (COM 1–2) support RS-232, RS-485, and RS-422 with hardware flow control for bidirectional device communication, while COM 3 and 4 provide RS-232 with hardware flow. A dedicated MAIN COM uplink connects to your control processor or PC, and a NEXT COM output enables daisy-chaining multiple expanders. Four relay outputs handle motorized screens, lighting, blinds, and door locks — enough to automate an entire satellite room from one device.\u003c\/p\u003e\u003cp\u003eDesigned for boardroom satellites, multi-device closets, classroom hubs, and backstage control, the CR-EXPAND4 connects to your control processor over 100M Ethernet using standard TCP\/IP and UDP protocols. Front panel LEDs provide real-time status for power, LAN, all four relay channels, and TX\/RX activity on every serial port — making on-site commissioning and troubleshooting fast. Where the CR-EXPAND1 serves single-device remote drops, the CR-EXPAND4 scales to locations with three or four controlled devices without the complexity or cost of deploying a full control processor.\u003c\/p\u003e","brand":"KanexPro","offers":[{"title":"Default Title","offer_id":49156215439530,"sku":"CR-EXPAND4","price":499.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/2966\/6474\/files\/CR-EXPAND4-zoom1.jpg?v=1787909831","url":"https:\/\/b2b.kanexpro.com\/products\/4-port-av-control-expander-serial-relay-ethernet","provider":"KanexPro B2B","version":"1.0","type":"link"}