Is there a charge for school time by mobile phone?

The software itself is free of charge, but if it is corrected through the network, it will charge traffic fee or SMS fee.

At present, there are three commonly used time corrections. The accuracy is: first, GPS time correction, which is not very clear, seems to receive GPS signals and synchronize with the time information on the satellite; The second is network time correction, which is linked to the network server for time correction; Third, short message time correction, sending short messages to the server to obtain time information.