1.Caller ID for C.O Lines and extension,telephone number is not lost when transferring .  
2.Outline calling on duty manual/automatic mode,Ringtone mode.  
3.Three-section of digital recording can be 20 seconds .(optional 30s-90s).  
4.When calling no one answer or the line is busy can be transferred .  
5.Calling level for extension and the talking time is limited .  
6.The extension number ranges can be mixed .  
7.Outline or inline calls can be answered the Phone for Others , transfer, retention, monitor .  
8.Checking telephone caller id number and voice checking .  
9.Automatic IP dial-up .  
10.Call center function, extension hotline number, Ringtone function.  
11.Automatic on duty and abbreviated dialling .  
12.Remote maintenance, hardware self-tested .