During connection subscribers can use DTMF combinations to invoke VAS.
Some VAS for DTMF combinations is embedded into the system.
You can redefine DTMF sequences, which are used to invoke this VAS, but cannot change the behavior of these VAS.
The bright examples are VAS Blind transfer and Attended transfer.
However besides this embedded VAS you can define your own VAS.
For them you can define both DTMF for activation and behavior of the system after that VAS has been activated.
The bright examples are VAS Connecting to conversation additional participants and Receiving fax during conversation.
Currently available DTMF combinations user can see in menu DTMF features.