Retrotronik RAM card for HP 48GX

[rprosperi]

128K cards should work in either slot of any 48SX/GX.

Tripod made some special 256K and 512K cards for the 48SX, but they required manual bank selection, done by commands in a small library. These cards cannot be used in a 48GX.

Conversely, the 256k-4096k (4MB) cards intended for the 48GX cannot be used in an SX. These cards also used bank switching techniques, but controlled and hidden by the OS.

So yes, these cards should work anywhere; perhaps the manufacturer considers only GX machines to still be in use and is therefor marketing only to them. It seems lots of surveyors still use 48GX's to this day, but I'm not aware of any that still use a 48SX.