i agree but i doubt any company will invest the cash into UL listing a new 4-wire LED device just for service stock though. they’ll just keep the old line alive until their orders get so low they can no longer justify it and force customers with 20 year old nac’s to upgrade or find another solution.
i can’t think of a single reason why anyone would’ve chosen a 4 wire horn/strobe over a 2 wire one in a new installation in the past 15 years. unless they just absolutely felt the need to double their wire for no reason… any ideas?
Audible scilence? Even though that can be accomplished with 2 wire circuits with the use of a sync module. I would also say coding, but it is required for code to be Temporal 3 which nearly all new appliances have. I guess these would be the most practical use of 4-wire devices. 4-wire devices also use a lot more current since both circuits are independent.
“Required for code”, possibly, but definitely not enforced. My building, which is only a couple years old, has TrueAlerts on continuous. The sounder smokes do go off with the building alarm, though, and those are code 3.
2-wire can do all of that, and audible silence has technically been against code since 2006, so hopefully most jurisdictions are at least up to that by now.