VoLTE

Understanding VoLTE in IoT & M2M Deployments

VoLTE stands for Voice over Long Term Evolution and is essentially a method for delivering voice services over a 4G LTE data connection. Traditionally, mobile voice calls were handled by 2G or 3G networks. However, as operators phase out these older technologies, voice services must now run over 4G – and that’s exactly what VoLTE enables.

In the context of IoT and M2M connectivity, VoLTE becomes relevant when:

• Devices require outbound or inbound voice calling (e.g. remote alarms, lifts, telecare units)

• A fallback voice channel is used for critical alerts alongside data

• A device or router includes voice-enabled SIM cards for business continuity or legacy compatibility

Unlike circuit-switched calls used by 2G/3G, VoLTE uses packet-switched voice carried over the LTE network. This allows devices to make voice calls while maintaining an active data connection – all over a single 4G channel.

Why VoLTE is Needed in a Post-3G World

The UK and global operators are well into their plans to switch off 3G and 2G networks – with some already fully retired. This poses a serious challenge for any business using legacy devices or SIM cards that relied on these networks for voice fallback or primary calling.

Without VoLTE support, a voice-capable device using a 4G-only SIM will not be able to make or receive calls once 3G is gone. This is particularly relevant for:

• Security panels that dial out
• Industrial routers with voice ports
• Telemetry units that include a voice fallback

Enabling VoLTE on the router, device, and SIM ensures that voice capability is retained – even as older mobile networks are decommissioned.

How It Works with M2M/IoT Routers and SIM Cards

To use VoLTE, three things must align:

• The SIM card must support VoLTE (some IoT/M2M SIMs do not by default)
• The router or device must be VoLTE-capable and properly configured
• The mobile network must support VoLTE on the chosen APN/profile

Some industrial 4G routers – especially those with voice ports or FXS interfaces – may be capable of VoLTE out of the box. However, others may require firmware updates or advanced configuration. Additionally, not all networks enable VoLTE on M2M SIM profiles by default, so it’s important to check compatibility.

Common Applications of VoLTE in IoT & M2M Environments

• Telecare & Medical Devices: Devices like emergency pendants or alarm systems that must dial out directly to carers or services
• Lifts and Elevators: Voice communication for trapped occupants or maintenance access
• Security Systems: Intruder alarms with dial-out functionality to control centres
• Rural Gate Entry & Intercom Systems: Where a voice connection is required alongside remote access

In all of these applications, VoLTE ensures seamless operation even in the absence of legacy networks.

How Millbeck Can Help

Millbeck supplies a range of 4G routers, SIM cards, and configuration services designed to support VoLTE-ready deployments. We can advise on:

• VoLTE-compatible routers for industrial or remote use
• SIM card profiles that include voice capability
• Preparing your devices ahead of the 2G/3G shutdown

If you’re deploying IoT or M2M devices that rely on voice – now is the time to check for VoLTE readiness.