Section: 4.5.1.5 MM connection establishment for emergency calls
Content: A MM connection for an emergency call may be established in all states of the mobility management sublayer which allow MM connection establishment for a normal originating call. In addition, establishment may be attempted in all service states where a cell is selected (see subclause 4.2.2) but not in the MM CONNECTION ACTIVE state (GROUP TRANSMIT MODE) state. However, as a network dependent option, a MM connection establishment for emergency call may be rejected in some of the states. When a user requests an emergency call establishment the mobile station will send a CM SERVICE REQUEST message to the network with a CM service type information element indicating emergency call establishment. If the network does not accept the emergency call request, e.g., because IMEI was used as identification and this capability is not supported by the network, the network will reject the request by returning a CM SERVICE REJECT message to the mobile station. The reject cause information element indicates the reason for rejection. The following cause values may apply: #3 "Illegal MS" #4 "IMSI unknown in VLR" #5 "IMEI not accepted" #6 " Illegal ME" #17 "Network failure" #22 "Congestion" #25 "Not authorized for this CSG" #32 "Service option not supported" #34 "Service option temporarily out of order" With the above defined exceptions, the procedures described for MM connection establishment in subclauses 4.5.1.1 and 4.5.1.2 shall be followed. NOTE: Normally, the mobile station will be identified by an IMSI or a TMSI. However, if none of these identifiers is available in the mobile station, then the mobile station shall use the IMEI for identification purposes. The network may in that case reject the request by returning a CM SERVICE REJECT message with reject cause: #5 "IMEI not accepted".