Just looked at the new manual , and it has + / - hold off ,sw-ve for siren and strobe is programmable.You could wire the -ve hold off through the tamper switch , this would only give limited tamper protection i.e. it wouldnt report to the panel.Or you could prog zone 29 or 30 as tamper , but would have to wire it separately.Or buy the visonic rf version.

Thanks Fastcar. I already have the wire there for the old bell so would prefer to go wired.

Two things about wireless sirens put me off:

- changing the batteries (it's bound to be raining!)

- if there's a comms problem, the panel may not be able to reset the siren

Thanks for the wiring help. Will try it as you suggested - especially if I get a new bell! Probably wire any tamper into one of the wired zones rather than as part of the hold off.

I am sure that Visonic make a Siren Output board specifically for the Powermax. You install it in a separate PSU, and wire the SAB to the module. That way you have no power probs

More ideas here :

TTS