Voice Calling on iPhone over a Private Network
A private network carries data only, but a user's normal phone calls can still travel over it. That gives you mobile voice coverage where the operator has none.
A private 5G or LTE network carries data only. Apple configures it that way on iPhone and iPad, so the Phone app and SMS keep using the mobile operator, not your network.
That matters less than it first appears, because the operator's calls can travel over your private network when the operator's own signal cannot reach. Users keep their number and their subscription, and get working calls in places that have never had them: inside a plant, deep in a warehouse, in a basement, behind steel and concrete.
Sites deploy private cellular because public coverage is poor. The same deployment fixes the voice coverage as a by-product.
How the call gets through
The iPhone runs two SIMs at once.
Private SIM
all data
your GXC network
Carrier SIM
calls and SMS, on the user's own number
whichever path below is available
The feature that carries the call is what Apple calls Wi-Fi Calling. The name is historical. It lets an operator's voice service run over any IP connection, and your private cellular network is one.
The handset does not prefer your network for voice. It uses it only when nothing else will carry the call:
1
The operator's own network
there is operator signal
2
Wi-Fi
no operator signal, but Wi-Fi is available
3
Your private network
neither of the above is available
In the yard, the call goes over the operator. In the office, over Wi-Fi. Deep in the plant where there is neither, over your network. Nobody configures anything per location, and the user cannot tell the difference.
What you need
Three things, and only one of them is yours to build.
An operator that supports Wi-Fi Calling, enabled on the user's subscription. Most major operators do. Confirm this first, because nothing else matters without it.
A dual-SIM iPhone, with the private eSIM provisioned alongside the user's existing carrier SIM.
Private network coverage where people need to call from, which is the coverage you planned for data anyway.
No gateway, no extra licence, and nothing further from GXC.
The limits
You cannot steer voice onto your network. If a call can reach the operator or a Wi-Fi access point, it will. The private path is a fallback, not a preference, and there is no setting that changes this.
It costs a subscription per person. Everyone who needs calls needs their own carrier plan. Across a large fleet of operational handsets, that adds up quickly.
It depends on the operator. A lapsed subscription or an operator outage stops calls. Your network cannot substitute for the service it is carrying.
When to use an application instead
Where the calling is internal, operator to supervisor or team to team, a push-to-talk or VoIP application on your own network answers better. It needs no operator, keeps audio on site, costs nothing per user, and supports group and priority calling, which an ordinary phone call cannot do.
Most sites end up running both: carrier voice to reach the outside world, an application for the floor.
For the people using the phones
Dial as you always have. Your number and your carrier have not changed, and data runs over the private network so apps stay fast on site.
One thing not to change: if you switch the phone to the carrier SIM for cellular data, it returns to the private SIM the next morning by itself. That is intended. If you need it changed for longer, ask your IT team.
Requirements
iOS 17 or later for private 5G and LTE support. iOS 18 or later for more than one private network on a device, or for switching by location.
An eSIM provisioned for your network, matching its mobile country code and network code. GXC issues these from Onyx Portal.
A device management profile. iPhone needs one before it will attach to a private network. Apple documents the payload in Support for private 5G and LTE networks.
Related
How do I add my iPhone to the GXC Network? : getting a handset onto the network, step by step
Manage Subscribers : provisioning SIMs and subscriber groups
Compatible Devices : which iPhone models are tested, and on which bands
Contact GXC
To get in touch with GXC, please visit https://gxc.io/contact-us/.
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