Question: Which interfaces are utilized for Location Services (LCS) signalling between Access and Core Networks specifically in GSM networks, as opposed to UMTS?
Option 1: Only Iu interface
Option 2: A, Gb, and Iu interfaces
Option 3: S1 and X2 interfaces
Option 4: Gn, Gp, and Gi interfaces
Explanation: In the context of telecom networks, particularly for GSM (Global System for Mobile Communications) as opposed to UMTS (Universal Mobile Telecommunications System), LCS signalling requires specific interfaces for communication between Access and Core Networks. The correct interfaces used in GSM for this purpose are indeed A (for circuit-switched services), Gb (for packet-switched services in GPRS core network), and Iu (common for both, facilitating communication with the UMTS core network for GSM/UMTS dual-mode networks). This highlights the nuanced difference in infrastructure requirements between GSM and UMTS for LCS signalling.