# CS Network - Circuit Switched Network Traditional method of establishing communication paths in telecom networks, primarily for voice services, where a dedicated circuit (or channel) is established for the duration of a transmission session between two endpoints (e.g., two telephones), and have gradually been replaced or supplemented by more efficient and versatile packet-switched technologies in newer generations of telecom networks. Key characteristics and context of [[CS Network - Circuit Switched Network|CS Networks]] in telecom evolution include: 1. **Voice Communication**: Initially used for voice calls in the first and second generations of mobile networks ([[1G - Analog cellular telephony|1G]] and [[2G - Digital cellular telephony|2G]]). 2. **Dedicated Path**: Establishes a dedicated and continuous connection for the duration of a call, which ensures consistent quality and reliability. 3. **Examples**: Traditional [[PSTN - Public Switched Telephone Network]] and early mobile networks like [[GSM - Global System for Mobile communication]]. 4. **Transition to IP**: With the evolution to [[3G - High-speed digital cellular telephony|3G]] and [[4G]] networks, there was a significant shift from [[CS Network - Circuit Switched Network|CS Networks]] to [[PS Network - Packet Switched Network|Packet Switched Networks]], especially with the introduction of [[VoIP - Voice-over IP]] and [[IMS - IP Multimedia Subsystem]] in [[LTE - Long Term Evolution]] networks, where voice and data services are integrated and transmitted over [[IP - Internet Protocol|IP]]. 5. **Coexistence with PS**: In [[3G - High-speed digital cellular telephony|3G]] networks, both CS and PS domains existed, allowing for both traditional voice services and newer data services over [[IP - Internet Protocol|IP]].