yes you have to inclide max | Microcontroller › 8051 › interfacing gsm sim300 modem with MC At89s52- doubt › yes you have to inclide max October 8, 2012 at 12:44 pm #8649 DexterParticipant yes you have to inclide max 232 after mc 89c52 make sure the cable rs232 internal wire rx tx gnd is connecter between the both max 232 in mc and sim 300
