One fellow ask me what does PSR stand for ! You know I was stumped . I have been on this sight many times and could not answer that questions. I was totally Embarrassed.
FYI
"PSR" stands for "PortaSound Regular."
"PSS" (which is sometimes seen among older used instruments) stands for "PortaSound Small."
"Regular" and "Small" refer to the sizes of the keys-- PSR models have regular-sized keys, whereas PSS models have miniature keys.
Older PSR models were usually just "PSR" followed by a number, but newer models are divided into the PSR-E and PSR-S lines.
The "E" in "PSR-E" stands for "Entry-level," but could also be read as "Educational," as the PSR-E models have the "Y.E.S." or "Yamaha Education Suite" feature.
The "S" in "PSR-S" stands for "Stage," as the PSR-S models are considered to be suitable for professional musicians.
PSR-S models have an implementation of XG, whereas PSR-E models have an implementation of XGlite.
"XG" stands for "eXtended General MIDI," Yamaha's extension of "GM" or "General MIDI."
("GM2" or "General MIDI Level 2" came later, hence GM is now also sometimes referred to as "GM1" or "General MIDI Level 1.")
"XGlite" is a "lite" version of "XG"-- it doesn't include all of the XG voices, and also omits some of the XG sound parameters and effects.
There are also several "localized" PSR models which use other letters, including-- but not limited to-- the following:
The "A" in "PSR-A" stands for "Arabic" or "Arabian."
The "B" in "PSR-B" stands for "Brazil" or "Brazilian."
The "I" in "PSR-I" stands for "India" or "Indian."
The "R" in "PSR-R" stands for "Russia" or "Russian."
The "VN" in "PSR-VN" stands for "VietNam" or "VietNamese."
The Portasound keyboards are/were also referred to as Portatone keyboards.
"YPT" stands for "Yamaha PortaTone."
The YPT models are equivalent to PSR-E models-- they generally share the same manuals-- e.g., the YPT-200 is equivalent to the PSR-E203.
A couple of the other Yamaha lines are as follows:
"DGX" apparently stands for "Digital Grand XG"-- although these models actually have an implementation of XGlite.
"YPG" stands for "Yamaha Portable Grand."
These are equivalent to each other-- they generally share the same manuals.
The DGX and YPG models differ from the PSR models in the number of keys-- the PSRs have 61 keys, whereas the DGX and YPG models have 76 or 88 keys.
The DGX and YPG models also differ from Yamaha's digital pianos-- their voices aren't as high-quality, but they have a lot more voices than the digital pianos.
The Tyros is essentially the ultimate or deluxe version of a PSR-S, as evidenced by their prices, number of voices, features, and capabilities.