What is VoLTE? How it works and what it means for multi-network SIMs
Mobile networks are evolving rapidly. As the UK moves away from legacy infrastructure like copper phone lines and older mobile networks, technologies such as VoLTE (Voice over LTE) are becoming an increasingly important part of modern communications.
For businesses relying on mobile connectivity, particularly for safety-critical systems like lift emergency phones, understanding how VoLTE works and how it interacts with multi-network SIMs is key to building reliable, future-ready communications.
What is VoLTE?
VoLTE stands for Voice over LTE, a technology that allows voice calls to be carried over 4G LTE mobile networks instead of older 2G or 3G networks.
Historically, when a mobile phone made a call, it would drop down from 4G data to an older network to complete the call. VoLTE removes this step by allowing voice to travel directly across the 4G data network.
This improves both efficiency and call performance. Calls can connect faster, audio quality is typically clearer, and devices can remain connected to data services during a conversation.
For organisations deploying modern mobile solutions, including business mobile connectivity, VoLTE helps deliver a smoother and more reliable user experience.
How does VoLTE work?
VoLTE works by converting voice into digital data packets, similar to how voice operates in VoIP phone systems. Instead of using the traditional circuit-switched technology that powered older phone networks, VoLTE sends voice traffic across the LTE network using internet protocol (IP).
This approach allows mobile networks to handle voice calls in the same way they manage other data services. As a result, calls are established more quickly and voice quality can be significantly improved, often referred to as HD Voice.
As mobile operators invest more heavily in 4G and 5G infrastructure, VoLTE is becoming the standard method for delivering voice services across mobile networks.
The impact of the 2G, 3G and PSTN switch-off
Across the UK telecoms industry, legacy infrastructure is gradually being retired. Older networks such as 2G and 3G are being phased out, while the traditional copper-based phone network is set to be switched off as part of the PSTN switch-off programme.
These changes are designed to modernise the UK's communications infrastructure and move services onto more efficient digital platforms.
For businesses that rely on connected devices, including alarms, payment terminals, monitoring equipment and lift emergency lines, this shift means ensuring their connectivity solutions are ready for a 4G- and IP-based future.
How multi-network SIMs work without VoLTE
Many safety-critical communication systems rely on multi-network SIM technology. These SIMs can connect to more than one mobile network, automatically selecting the strongest available signal at any given time.
This capability is particularly valuable for applications like lift SIM solutions, where consistent connectivity is essential.
However, multi-network SIMs often operate differently from consumer mobile SIMs when it comes to VoLTE.
VoLTE requires a close integration between the SIM provider and the mobile network operator, including device certification and specific network configurations. Because multi-network SIMs can switch between multiple operators, maintaining a consistent VoLTE configuration across every network can be more complex.
For this reason, many multi-network deployments rely on alternative methods of maintaining voice or data connectivity. The focus instead is on ensuring resilient network access, allowing devices to stay connected even when coverage from a single operator is unavailable.
In environments where reliability matters more than any single network feature, this flexibility becomes a significant advantage.
Why multi-network SIMs remain ideal for critical connectivity
While VoLTE improves voice performance on single-network mobile devices, multi-network SIMs provide resilience. By enabling devices to automatically connect to different mobile networks, they reduce the risk of a communication failure caused by poor coverage from one provider.
For systems such as lift emergency communication, the ability to maintain connectivity across multiple networks can be more valuable than relying on a single network’s voice technology.
As businesses modernise their communications infrastructure and prepare for industry changes like the PSTN switch-off, multi-network SIMs continue to play a key role in maintaining reliable connectivity.
Preparing your connectivity for the future
Technologies such as VoLTE are part of a wider shift towards fully digital communications networks. Understanding how these technologies interact with solutions like multi-network SIMs helps businesses make more informed decisions when reviewing their telecoms infrastructure.
Whether you're upgrading employee devices, deploying IoT systems or ensuring lift emergency lines remain compliant, the right connectivity approach can make a significant difference.
At Blend Telecom, we help organisations design communications solutions that combine resilience, simplicity and future readiness. From business mobiles to multi-network SIM connectivity and business broadband solutions, our focus is on delivering connectivity that works reliably in the real world.
If you're reviewing your current setup or preparing for upcoming network changes, our team can help ensure your communications remain ready for what comes next.
Contact us to book your free technology audit today.
