Hotel communication solution with bus shuttle fleet
November 10, 2025
Push-to-Talk over Cellular (PoC) and Radio over IP (RoIP)
Push-to-Talk over Cellular (PoC) is a modern way to deliver two-way radio style communications using existing IP networks. It is often referred to as Radio over IP (RoIP) because voice traffic is carried over the internet rather than traditional RF-only radio systems.
Just like Voice over IP (VoIP) sends phone calls over the internet, RoIP sends two-way radio audio over IP networks so users can communicate with a single push of the PTT (push-to-talk) button.
How PoC / RoIP Works
PoC and RoIP take the familiar user experience of a two-way radio and route it through cloud services and IP networks instead of local radio repeaters.
1. Data plan SIM card
Each PoC device (handheld two-way radio) includes a:
- Data plan SIM card, similar to a smartphone SIM
- Connection to 4G / LTE / 5G networks provided by Mobile Network Operators (MNOs)
This SIM gives the radio access to the internet through the carrier’s cellular infrastructure.
2. IP connection to cloud-based PoC services
Once the device is online, it connects over the internet to a cloud-based PoC service. This PoC platform:
- Authenticates the user and device
- Manages talkgroups and user permissions
- Routes voice traffic between users, groups, and dispatch consoles
From the user’s point of view, they simply press the PTT button and talk. Behind the scenes, voice is digitized and sent as IP data through the cloud.
3. Push-to-talk over 4G/5G/LTE and Wi-Fi
PoC devices can use:
- 4G / LTE / 5G cellular networks for wide-area coverage
- Wi-Fi networks where available, such as indoors, campuses, or facilities
As long as the device has an IP connection (cellular or Wi-Fi), it can reach the PoC cloud controller and participate in group calls and private calls.
Hytera PoC Devices and HORIZON Nationwide PoC
Hytera PoC devices are purpose-built handheld radios designed to work with PoC services. They look and feel like traditional two-way radios, with:
- A dedicated PTT button
- Loud, clear audio
- Rugged housing for professional use
However, instead of relying only on RF channels, they use IP networks for wide-area communication.
When paired with the HORIZON Nationwide PoC cloud controller:
Hytera PoC devices connect to the HORIZON PoC platform over the internet- Devices use 4G / 5G / LTE cellular networks and Wi-Fi to reach the cloud
- The HORIZON controller manages:
- Nationwide talkgroups
- User and device permissions
- Call routing and call history
- Features like GPS location and emergency alerts
This architecture allows wide-area and even nationwide coverage without installing your own RF repeaters or building a complex multi-site radio system.
Benefits of PoC / RoIP with Hytera and HORIZON
Using Hytera PoC devices with the HORIZON Nationwide PoC solution provides several advantages:
- Wide-area coverage
Coverage is tied to the cellular and Wi-Fi footprint, not a single radio site, so users can talk across cities or regions where network coverage exists. - Cloud-based control
The HORIZON PoC controller is hosted in the cloud, which simplifies deployment, updates, and scaling as your fleet grows. - Familiar two-way radio operation
Users still press a PTT button and talk in real time with individuals or talkgroups, just like traditional two-way radios. - Flexible connectivity
Devices can roam between 4G / 5G / LTE and Wi-Fi, maintaining communication as long as an internet connection is present. - Reduced infrastructure burden
Organizations do not need to build and maintain their own wide-area RF infrastructure, since the system uses existing carrier and IP networks.