HC-12 T Commands

AT Command	Purpose	Example	HC-12 Response	Notes
AT	Check comms	AT	OK
AT+Bxxxx	Set Baud rate	AT+B9600	OK+B9600	The baud rate can be 1200bps, 2400bps, 4800bps, 9600bps, 19200bps, 38400bps, 57600bps, or 115200bps. The default is 9600bps.
AT+Cxxx	Set channel number	AT+C012	OK+C012	Channel numbers are from 001 to 127 although over 100 the performance can't be guaranteed. The working frequencies start at 433.4MHz and go in 400KHz steps thus channel 100 is at 473.0MHz. When a particular channel is used a gap of five channels should be left on adjacent systems to avoid interference and desensitization.
AT+FUx	Set transmission mode	AT+FU3	OK+FU3
AT+Px	Set transmission power	AT+P3	OK+P3	Transmission power (x) can be set to 1 to 8 representing powers from -1dBm (0.8mW) to 20dBm (100mW) in 3dBm steps. The default setting is 8, 20dBm (100mW).
AT+Ry	Request a current setting	AT+RB	OK+B9600	Request the currently set status of the module. AT+RY returns the baud rate, AT+RC returns the channel number, AT_RF returns the transmission mode, and AT+RP return the transmission power.
AT+RX	Request all current settings	AT+RX	OK+FU3 OK+B9600 OK+C001 OK+RP:+20dBm	All the current settings are returned togther
AT+Udps	Set data format	AT+U801	OK+U801	This sets the number of data bits (d), the parity (N = none, O = odd, and E = even), and stop bits (1 = one stop bit, 2 = two stop bits, and 3 = 1.5 stop bits).
AT+V	Request the module's current firmware version	AT+V	OK+HC-12_v2.3
AT+SLEEP	Enter sleep mode	AT+SLEEP	OK+SLEEP	Enter sleep mode on exiting command mode. Power cycling wakes the module up again
AT+DEFAULT	Sets default values for all parameters	AT+DEFAULT	OK_DEFAULT	This sets the module to 9600bps, 8 data bits, no parity, 1 stop bit, channel 001, and transmission mode FU3.
AT+UPDATE	Prepare for new firmware			Puts the module into update mode waiting for new firmware. Power cycle to return to normal operation.

All commands must be sent at 9600bps, 8n1 mode regardless of any transmission settings.