The HP R5000 R7000 and possible R/T3000 can be set up to initiate a shutdown on the attached devices via network. Normally using the AF465a network card
This system has some strange behaviour. Firstly the web interface has unusual naming - for example the main status page is titled "POWER SOURCE" and it can have things like battery status: aborted listed. The charge levels of the cell can stick at 96%. Plenty of strange stuff, a lot of which you can work with.
Setting up auto shutdown of attached devices is harder than it should be because of illogical design and poor terminology. We are going to record pertinent information here to help people in the future.
This image shows part of the AF465a card documentation - it shows how if you set the "Shutdown initiated after" value to 0 seconds it will run the UPS till it dies without sending a shutdown signal to the attached devices.
This is counter intuitive, as if you set it to 10 seconds, the UPS would send the signal after 10 seconds, if you set it to 1 second, then one second after input power interruption it would send the signal, and you would think if set to zero it would send it straight away, but in fact it never sends it.