The Egyptian hieroglyphic script contained 24 uniliterals (symbols that stood for single consonants, much like English letters) which today we associate with the 26 glyphs listed below.
(Note that the glyph associated with w/u also has a hieratic abbreviation.)
The traditional transliteration system shown on the left of the chart below is over a century old and is the one most commonly seen in texts.
It includes several symbols such as 3 for sounds that were of unknown value at the time.
[1] Some scholars believe that consonants transcribed as voiced (d, g, dj) may actually have been ejective or, less likely, pharyngealized like the Arabic emphatic consonants.