Video intercoms · Dahua 2-wire field guide
Pressing Monitor on the indoor screen should show the gate camera. Instead you get an error that sounds like a network outage and almost never is.
Part 2 of 7 · By Gareth Barber, Owner & Head Locksmith, Access Locksmiths · Published 2026-10-05
Pressing Monitor on the indoor screen returns: "Failed to monitor. The network is abnormal."
It's a misleading message. It almost always means the monitor is looking for the door station at the wrong address.
The monitor stores a list of door stations — the VTO Set list (internally VTOInfo / RemoteDevice). Each entry has a name, such as "GATE", and an IP address. When you press Monitor, the screen connects to the address stored in that entry to pull the video.
If that address is stale (the door station's old IP), blank, or — as we found — pointing at the monitor's own IP, there is nothing to stream and you get "network abnormal". On our deployment the list had been scrambled:
Vto00 -> 192.168.0.60 name "GATE" correct target (the door station)
Vto01 -> 192.168.0.214 name "GATE" pointed at the MONITOR ITSELF (wrong)0.0.0.0 or at the monitor's own IP.If the monitor has no browser UI — ours didn't — the same fix can be made remotely through the RPC2 API rather than the on-screen menu. See Part 5.
The monitor was on DHCP. Every power-cycle — re-mounting it on the wall was enough — could hand it a new address, which broke its link with the door station. The lasting fix is a static IP on the monitor.
The monitor also registers to the door station over SIP. Its SIPServer and OutboundProxy must point at the door station's current IP as well. The device-list address and the SIP address both have to be right, or you will still see failures.
Written from one real deployment. Client-identifying details have been removed; technical values are generic examples. Firmware and hardware generations differ — verify each step against your own models. Corrections are welcome and will be published with attribution.