From January 27, 2025, Telefónica will definitively close its circuit-switched fixed telephone network, a system that has operated for decades and was fundamental to telecommunications in Spain. The historic TDM (Time Division Multiplexing) network, which allowed for voice call management on the public network, will be entirely replaced by Voice over IP (VoIP) technology, marking a milestone in the evolution of the country’s telecommunications infrastructure.
The TDM network, which had been in operation since the early days of fixed telephony in Spain, connected millions of users using the SS7 protocol (Signaling System No. 7) for data and call exchange. However, with the rise of fiber optics and mobile technologies like 4G and 5G, Telefónica has decided to transition to a VoIP-based network, aligning with the needs of the digital era.
The shift towards VoIP: a necessary evolution
In recent years, IP telephony traffic has experienced exponential growth. While in 2019 only 19.5% of call traffic in Spain was managed through IP, currently this figure exceeds 98%, and it is expected to reach 100% with the shutdown of the TDM network.
This move is not just a technological evolution, but also a response to the challenges of maintaining outdated infrastructure. According to Telefónica, one of the main issues is the lack of spare parts for TDM systems, which rely on equipment with over 30 years of lifespan. Additionally, the loss of specialized personnel in this technology and the high energy consumption of the traditional network compared to the efficiency of VoIP have hastened the decision to disconnect it.
CNMC approval and impact on operators
The National Commission of Markets and Competition (CNMC) has given the green light to the shutdown of the 49 TDM switches still operating in Spain. These switches, distributed in 21 nodal areas, have been the interconnection point between Telefónica and other operators for years, allowing users from different companies to connect. However, with the transition to IP interconnection, this system has become obsolete.
In its resolution of September 20, 2024, the CNMC authorized Telefónica to proceed with the total shutdown of the TDM network, noting that only 0.2% of inter-operator traffic currently flows through this network. The regulatory body has also notified the European Commission and other EU member states of the measure, ensuring a smooth transition to the new VoIP system.
A step towards the future of telecommunications
With the shutdown of the TDM network, Spain joins other countries that have already abandoned this technology in favor of more modern and sustainable solutions. The use of VoIP not only improves energy efficiency, but also enables better call quality and advanced communication services like video calls and instant messaging.
This change is part of a broader process of modernizing telecommunications networks, including the shutdown of 2G and 3G mobile networks, and the complete migration to fiber and 5G technologies. David Carrero, Internet entrepreneur since 1994 and co-founder of Stackscale (Aire Group), commented: “Spain continues to be a leader in telecommunications, and the transition to VoIP is another step towards ensuring quality, secure, and efficient service in the future.”
With this change, January 27, 2025, will be marked as the end of an era in Spanish telecommunications, where technologies of the past make way for solutions of the future.
Source: BandaAncha and BOE