3.7 MutePress Mute button during the conversation, icon will be showed in the LCD.Then the called will not hear you, but you can hear the called. Press it again toget the phone to normal conversation.3.8 Call transfer1. Blind TransferDuring talk, press the key Transf, and then dial the number that you want totransfer to, and finished by "#". Phone will transfer the current call to the thirdparty. After finishing transfer, the call you talk to will be hanged up. User cannot select SIP line when phone transfers call.2. Attended TransferDuring talk, press the key Transf, then input the number that you want totransfer to and press Send. After that third party answers, then press Transfer tocomplete the transfer. (You need enable call waiting and call transfer first).3. Alert TransferDuring the talk, press Transf firstly, and then press Send after inputting thenumber that you want to transfer. You are waiting for connection, now, pressTransf and the transfer will be done. (To use this feature, you need enable callwaiting and call transfer first).3.9 3-way conference call1. Press the Conf softkey during an active call.2. The first call is placed on hold. Then you will hear a dial tone. Dial thenumber to conference in, then press Send key.3. When the call is answered, press Conf and add the first call to theconference.4. If you want to release the conference, press Split key.Note: the server that user uses must support RFC3515 or it might not be used(User must enable call waiting and three way call first).3.10 Multiple-lineIn this phone you can registe 6 SIP account numbers and the 6 accuonts can be used atthe same time.There are four keys used as SIP line toleranted to make calls in SIPaccounts.It will blink when the account registed failed.