After the telephone switch is normally opened and used, when it is in the maintenance operation stage, it often fails due to program operation errors. This requires the maintenance personnel to handle such failures in a timely manner to ensure the smooth communication. The so-called handling of failures can also be understood as the process of placing software control programs in a normal operating state.

When the telephone exchange software program is wrong or confusing, there is no time for the maintenance personnel to study the working principle of the software program itself. As long as the troubleshooting is implemented as soon as possible and the telephone can be promptly rushed through. The use of restart methods to quickly eliminate program failures has become a "magic bullet" for maintenance personnel. This is similar to the fact that when we operate a computer, when a "dead" phenomenon occurs due to a computer program error, no matter what kind of commands the keyboard is typing, the computer will not respond. At this time, the fastest way to recover is to "hot" the computer. "Start or "cold" start. Similarly, the telephone exchange can also use the restart method due to the need to handle its program failures.

For different models of different types of telephone exchanges, the operating mode and command parameters of the telephone exchange may be different when the program is restarted. However, the functions and types of the restart are roughly the same. It is nothing more than using commands to restart the software program or operating the hardware. The group restarts.