.PHO File Extension

File created by printed circuit board (PCB) design applications; contains a photoplot, which is a generated image of a PCB design that can be used in the process of manufacturing PCBs; often generated from a .GBR file and can be viewed in several Gerber compatible applications.

Audio data file used by MBROLA, a speech synthesizer used for generating speech audio in multiple languages; contains a list of phonemes, which are the basic audible units of speech, as well as the duration for each phenome; used for generating .WAV, .MP3, or other audio files with human speech.

NOTE: PHO files themselves are not playable audio files, since they only contain the data required to generate human speech audio when input into MBROLA.