4-Port AV Control Expander — Serial, Relay & Ethernet New

Some remote locations need more than a single control drop — but not a full processor. 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.

Designed 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.

• MAIN COM (RS-232) + 4 extended serial ports — 5 serial connections total
• COM 1–2: RS-232/RS-485/RS-422 with hardware flow control
• COM 3–4: RS-232 with hardware flow control
• NEXT COM daisy-chain output for cascading multiple expanders
• 4× relay outputs, normally open (1A 24VDC/AC)
• 10/100M Ethernet with TCP/UDP — TCP ports 8001–8004 per serial
• Built-in web server for browser-based configuration
• DC 24V/1A power (24V adapter included) — no PoE
• Front panel LEDs: PWR, LAN, 4× relay, MAIN TX/RX, COM 1–4 TX/RX
• Metal enclosure: 147mm × 130mm × 42mm, 673g