Question: What is the requirement for a Phase 2 Mobile Equipment (ME) when interacting with a Subscriber Identity Module (SIM) that only complies with Phase 1 mandatory requirements?
Option 1: The ME must only use Phase 1 commands to ensure compatibility.
Option 2: The ME can ignore potential incompatibilities arising from RFU bytes interpretation differences.
Option 3: The ME is not required to support such SIMs for any operations beyond basic call setup.
Option 4: The ME must support the SIM while mitigating potential incompatibilities, including cautious handling of RFU bytes.
Explanation: This answer reflects the requirement that Phase 2 MEs must support Phase 1 SIMs and take care to avoid incompatibility issues, including being mindful of how Reserved For Future Use (RFU) bytes are interpreted, as their meaning can change between phases.