Introduction - If you have any usage issues, please Google them yourself
SCM stc89c52 and GSM (sim300) modules, specific content is sent using a mobile phone to GSM a0# (Note: # is the English characters, not Chinese characters), GSM will start a relay to control the microcontroller, while the microcontroller returns qi dong send to a GSM module, GSM mobile phones to send text messages to a specified number using a mobile phone to send a1#, the relay will be closed while sending guan bi to the designated phone number. A total of three relays can be controlled separately with the message content for a0#, a1#, b0#, b1#, c0#, c1# control off ( 0 through 1 for the break)