PhoenixBIOS is a type of BIOS produced by Phoenix Technologies. Most modern motherboard manufacturers have integrated Phoenix Technologies' PhoenixBIOS into their systems.
Common Beep Codes on Computers (Most Common Codes – Phoenix BIOS)
There are several modified implementations of the PhoenixBIOS system on many popular motherboards. The beep codes of a Phoenix-based BIOS can be exactly the same as the real Phoenix beep codes below, but they can also differ. You can always check your motherboard manual to be sure.
A single beep from a Phoenix-based BIOS is actually an "all systems clear" message. Technically, it's an indication that the Power On Self Test (POST) is complete. No troubleshooting required!
One continuous beep is not an officially listed Phoenix beep code, but we know of multiple cases where it occurs. In at least one case, the solution was to reseat the CPU.