Schneider Electric Telemecanique 499-NES-251-00 Ethernet Switch

The Schneider Electric Telemecanique 499-NES-251-00 Ethernet Switch is an unmanaged ConneXium device designed for industrial Ethernet networks, delivering reliable PLC-to-HMI and controller communication in control panels, manufacturing lines, and process automation equipment. It provides five 10/100Base-TX RJ45 ports with auto-negotiation, auto-MDI/MDIX, and auto-polarity, using store-and-forward switching, a 1,024‑address MAC table, and 64 KB of buffer memory for steady data flow. Powered from 19.2–30 VDC (nominal 24 VDC SELV), it can be DIN-rail or panel mounted, is IP20-protected, and supports up to 100 m cable runs on CAT5 (or better) in 0°C to 60°C industrial environments; it complies with IEEE 802.3/802.3u and carries UL 508 and CSA 1010 certifications. Common replacements include Schneider Electric TCSESU053FN0, and it is commonly used for PLCs, HMIs, SCADA, conveyors, packaging, and other automation networks requiring dependable Ethernet communication.