HC-12 module has three serial pass-through mode, using FU1, FU2 and FU3 said. When used, the various models are just to send and receive serial data, wireless transmission portion of the air tube. The default work under FU3 full mode, which automatically adjusts air baud serial port baud rate according to at low baud communication distances. Different modes can not exchange data, the user can select the optimal mode according to the actual situation.
When using generally do not limit the number of bytes to a continuous serial transmission module. However, in view of factors such as environmental disturbance, when a large amount of data sent continuously, there may be missing some bytes. So, the PC is best to have the response and retransmission mechanisms to avoid loss of information.