VoNR in Routers and IoT Devices

Key point

VoNR in an industrial router or IoT device requires a 5G SA-capable module with IMS firmware, a 5G SA network at the deployment site, and a SIM provisioned with ISIM credentials. Most 5G modules currently on the market are 5G NSA only and do not support VoNR. Plan for VoNR compatibility now; the hardware replacement cycle is 5-10 years.

Module requirements for VoNR

A cellular module must have all of the following for VoNR capability:

5G SA support (NG-RAN interface, 5GC connectivity)
IMS stack in firmware supporting VoNR (SIP over 5G SA bearer)
5QI 1 QoS flow management
EVS codec support in the audio subsystem
EPS Fallback support (for continuity when moving out of 5G SA coverage)
Audio interface (PCM / I2S / USB) for voice endpoint connection

Current 5G module landscape

Module family	Examples	5G SA	VoNR	Notes
5G NSA data modules	Quectel RM500Q, RM502Q	Limited / NSA	No	High-speed data; no SA core support
5G SA capable modules	Quectel RM520N-GL, FM350	Yes	With IMS firmware	Confirm IMS/VoNR option at order
5G SA voice gateways	Emerging product category	Yes	Yes	PSTN replacement for 5G SA sites
Cat 1 / Cat 4 (4G)	Quectel EC21, EC25	No	No	4G only – VoLTE capable (see voltesim.co.uk)

Planning for VoNR – not yet but soon

For most IoT and industrial deployments today, VoLTE on 4G is the correct voice mechanism – 5G SA coverage is not yet widespread enough for VoNR to be a primary specification requirement. However, hardware selected now will be in the field for 5 to 10 years. Engineers specifying cellular voice-capable equipment in 2025 should:

Select modules that support 5G SA (not just 5G NSA), even if VoNR is not immediately needed
Confirm that the module firmware can be updated to add VoNR capability as it becomes available
Ensure the IMS stack is either present or can be added via firmware update
For current voice requirements: use VoLTE on a 4G module with ISIM SIM (see voltesim.co.uk – Routers and IoT)

Network slicing for industrial voice

For industrial deployments where voice quality and latency guarantees are required – critical communications, remote command and control, voice-enabled safety systems – VoNR on a dedicated 5G SA network slice provides the mechanism to contractually guarantee QoS. This requires working with the operator’s enterprise team to define a private or public slice with the required parameters, alongside 5G SA-capable hardware and correctly provisioned SIMs.