History : AT a ATX a BTX

These specifications define not only the form-factors, dimensions etc. but also the power supply required; therefore the name “ATX PowerSupply”. Extension of ATX PowerSupply-Specification: ATX a ATX12V (with extension of the 12V-rails, e.g. extra 4-pin for P4) ATX12V Mainboard-connectors : 20-pin + 4 (Single-CPU-M/B) or : 24-pin + 8 (Dual-CPUs M/B or higher) Important : The ATX12V 24-pin connector is similar and compatible to SSI / EPS12V , which having the same 24-pin connector (exception: without –5VDC on Pin#21, NC: No Connection) TG480-U01 (w/ 24-pin +8-pin) can therefore be used as EPS12V power supply ! Glossary : SSI : S erver S ystem I nfrastructure EPS : E ntry-level P ower S upply EPS12V : E ntry Non-redundant P ower S upply (w/ +12V extension) ERP12V : E ntry R edundant P ower S upply (more in: http://www.ssiforum.org/html/adoptedspecs.asp )