Section: 4.3.2 Change of UE mode of operation 4.3.2.1 General
Content: The UE mode of operation can change as a result of e.g.: - a change of UE's usage setting for a CS voice capable UE; - a change of voice domain preference for E-UTRAN as defined in 3GPP TS 24.167[ 3GPP IMS Management Object (MO); Stage 3 ]  [13B] for a CS voice capable UE; - a change in the UE's availability for voice calls in the IMS; or - a change in UE configuration regarding the use of SMS as defined in 3GPP TS 24.167[ 3GPP IMS Management Object (MO); Stage 3 ]  [13B]. Figure 4.3.2.1.1 and figure 4.3.2.1.2 illustrate the transitions between different UE mode of operations when UE's usage settings, voice domain preference for E-UTRAN or configuration regarding SMS changes. NOTE 1: The UE may transit from CS/PS mode 1 to PS mode 1 or from CS/PS mode 2 to PS mode 2 if "CS domain not available" is received. After the transition to PS mode 1 or PS mode 2 due to "CS domain not available", the UE can transit back to CS/PS mode 1 or CS/PS mode 2, e.g. due to change of PLMN which is not in the list of the equivalent PLMNs. NOTE 2: Not all possible transitions are shown in this figure. Figure 4.3.2.1.1: Change of UE mode of operation for a CS voice capable UE NOTE: Not all possible transitions are shown in this figure. Figure 4.3.2.1.2: Change of UE mode of operation for a UE with no CS voice capability