Will the RPS II RPS2 ) work with a cell phone?

Yes.  The phone just needs to generate the standard DTMF  tones for the RPS II to respond.  Some cell phones make a short tone beep, but you should be able to adjust the tone length within the cell phones system.  Just press the number on the keypad when connected to a call.  If the tone is continuous  few seconds ) it should be fine.  If not, find the configuration option that will adjust the tones length.