You need to use 5v to 3V | Microcontroller › PIC › plss help me to establish PIC to GSM serial communication › You need to use 5v to 3V May 8, 2012 at 5:50 pm #7654 AJISH ALFREDParticipant You need to use 5v to 3V level shifter IC. I don’t think it can be done with something like zener diode, because the voltage corresponding to logic 0 and logic 1 are different in 3v-logic and 5v-logic.
