Question: When a Mobile Equipment (ME) handles an IMS URI as a called address, how does it perform the Fixed Dialling Number (FDN) check, according to 3GPP specifications?
Option 1: The ME only checks the destination address against the EFFDN entries.
Option 2: The ME checks the destination address using both the EFFDN entries and the FDN stored in EFFDNURI, applying principles for URI handling.
Option 3: The ME skips FDN checking for IMS URIs, as it's not applicable to supplementary service operations.
Option 4: The ME relies solely on service principles for all FDN checks, without additional considerations for IMS URIs.
Explanation: This is correct because, according to the specifications, when dealing with an IMS URI as a called address, the Mobile Equipment (ME) must perform a comprehensive check. This involves verifying the destination address against both standard EFFDN entries and the FDN stored in EFFDNURI, adhering to principles for handling traditional numbers and URIs.