Section: 5.5.1.3 Combined attach procedure for EPS services and non-EPS services (S1 mode only) 5.5.1.3.1 General
Content: The combined attach procedure is used by a UE in CS/PS mode 1 or CS/PS mode 2 of operation to attach for both EPS and non-EPS services, or both EPS services and "SMS only". The combined attach procedure is also used by a UE in CS/PS mode 1 or CS/PS mode 2 of operation to attach for EPS services if it is already IMSI attached for non-EPS services. When the UE initiates a combined attach procedure, the UE shall indicate "combined EPS/IMSI attach" in the EPS attach type IE. The combined attach procedure follows the attach procedure for EPS described in clause 5.5.1.2 with exception of clause 5.5.1.2.4A and clause 5.5.1.2.6A.