有测试提了这么个问题，在下面的用例下，MS4打给MS1，有来电提醒么？：
啊，超过三个了，这个是MultiParty Call了。以前知道，但是从没有仔细看过。真的有人这么测试。
关键是，这个用例在国内测试不起来哎。实测移动下，即使开通呼叫等待，也根本不会有MS4的来电提醒。MS4只听到对方正在通话中。
但是如果网络支持，要如何测试呢？
看看协议呗。3GPP的TS22.084（MultiParty (MPTY) Supplementary Services - Stage 1），和TS22.030（ Man‑Machine Interface (MMI) of the Mobile Station (MS) ）
multiparty定义如下:
A precondition for the multi-party service is that the served mobile subscriber is in control of one active call and one call on hold, both calls having been answered. In this situation the served mobile subscriber can request the network to begin the multiParty service.
Once a multiParty call is active, remote parties may be added, disconnected or separated (i.e. removed from the multiParty call but remain connected to the served mobile subscriber).
The maximum number of remote parties is 5.
multiparty 对应的激活查询code:
mltiparty通过键盘操作spec如下:
Having established calls to these two parties with one call active and the other on hold, enter 3 followed by SEND for a multiparty conversation.
To add another remote party, the same procedure applies. Another call is established and either this call or the existing multiparty call is placed on hold. Entering 3 followed by SEND brings all these parties together in an enlarged multiparty call.
To choose one party for a private communication, putting the rest of the multiparty on hold, enter 2X followed by SEND, where X defines the call with which communication shall be supported.
To return to the multiparty, with the previously active call placed on hold, enter 2 followed by SEND.
To release a specific party enter 1X followed by SEND, where X is defined as above.
If the served mobile subscriber enters END, all calls including the multiparty are released. The multiparty is terminated.
Structure of the MMI
The following sequence of functions shall be used for the control of Supplementary Services:
SELECT: Entry of the procedure information (may be a digit or a sequence of characters).
SEND: Transmission of the information to the network.
INDICATION: Call progress indications.
The UE shall support the MMI procedure specified as:
Activation : *SC*SI#
Deactivation : #SC*SI#
Interrogation : *#SC*SI#
Registration : *SC*SI# and **SC*SI#
Erasure : ##SC*SI#
This structure consists of the following parts:
- Service Code, SC( (2 or 3 digits);
- Supplementary Information, SI (variable length).
The procedure always starts with *, #, **, ## or *# and is finished by #. Each part within the procedure is separated by *.
The service code uniquely specifies the Supplementary Service, either as a defined Supplementary Service or as a spare service code. All spare service codes shall be reserved for future use.
The UE shall determine from the context whether, an entry of a single *, activation or registration was intended.
For example, a call forwarding request with a single * would be interpreted as registration if containing a forwarded-to number, or an activation if not.
The supplementary information (SI) may comprise e.g. a PIN code or Directory Number. Where a particular service request does not require any SI, "*SI" is not entered, e.g. Activation becomes *SC#SEND. Where further supplementary information is required this is again entered as *SI, e.g. *SC*SIA*SIB#SEND. SIB may be used to specify the tele or bearer service expressed as a Basic Service Group to which this supplementary service request applies, SIC may be used to specify the value of the "No Reply Condition Timer".
附加业务对应的service code
