In the audio industry in general, 1/8" mini-phone plug and 3.5mm phone plug
mean the exact same thing. 

These "phone plugs" were based on the 1/4" phone plug as used for electric
guitars and their amplifiers, which was the original type of plug used by
telephone switchboard operators connecting calls on their patchbays. Hence 
the name "phone plug." 

The 1/8" (aka 3.5mm) version is the miniature version.
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