2Function
The command is used to deregister mobile subscribers from the
Visitor Location Register (VLR).

The operator can deregister mobile subscribers by specifying
their IMSI or can deregister all visiting mobile subscribers
belonging to a specified HLR.

Idle mobile subscribers are deregistered immediately and busy
mobile subscribers are deregistered when they become idle.

For deregistration of IMSIs the result printout
MT SUBSCRIPTION DEREGISTERED is produced to show the
deregistration status and the result of MS Purging for each
specified IMSI.

Up to 16 IMSI numbers may be given in one command.
For deregistration of HLR number the result printout
MT SUBSCRIPTION DEREGISTERED is produced when all idle
mobile subscribers have been deregistered and all busy
mobile subscribers have been marked to be deregistered.

The command for deregistration of IMSIs can be given from
16 I/O devices simultaneously.

The command for deregistration of HLR number can be given
only once.

When more than one I/O device is used, the two formats
can not be used at the same time.

The order remains after system restart.
這是ALEX的英文解釋。
其實這個問題的答案，自己看看英文就行了。不用問別人了。