O16 said:
I suggest using "analog_cellphone" or something alike.

Analog phones are these things here:
post #679794 post #92255
Preferably with a girl operator on the other end, because the stepper thingy they used is arguably a kind of proto-digital tech. Everything past that era is digital.

Cellphones that aren't smartphones are sometimes called "dumbphones". Alternatively, maybe tag smartphones as such and use cellphone for anything that's cellular but not a smart-phone.