Question: What is a key aspect of the UE access procedure that may vary between different types of User Equipment (UE) as per 3GPP specifications?
Option 1: The method for entering the PIN-code, which is standardized across all UEs.
Option 2: The sequence of events for UE access, which can be chosen by manufacturers.
Option 3: The requirement for a subscriber-card insertion, mandatory for all UEs.
Option 4: The use of a Mealy-graph for describing UE access procedures, unique to each UE type.
Explanation: The correct answer highlights the flexibility allowed by 3GPP specifications in the UE access procedure. While the overall process (e.g., inserting a subscriber-card and entering a PIN-code) is outlined, the exact sequence of these events can be determined by the manufacturers, enabling customization based on UE complexity or design. This variation accommodates diverse user interfaces and operational flows across different devices, from simple hand-held UEs to more complex stations.