RS1.FLEX.MONITOR

A daemon holds an open connection to the FlexRadio 6700 and subscribes to its state: every slice receiver, its frequency, mode and band, which one is armed for transmit, which client is driving it, and whether the radio is transmitting this instant. It also watches the SmartLink cloud registration separately, so “the radio is up” and “the radio is reachable from outside” are two different answers rather than one hopeful one.

The interesting part of this module is what it does when the radio disappears without saying goodbye. A radio that loses power does not close its socket — it simply stops talking, and a naive monitor will happily report a dead radio as healthy for as long as you let it. So there are three independent defences: TCP keepalive so the kernel probes a silent peer, a periodic command down the socket so there is traffic to fail on, and a staleness guard that refuses to publish “up” when nothing has actually arrived. Any one of them catches it. All three are there because this module's whole value is being trusted when it says the station is fine.