Push-to-talk over cellular
Push-to-talk over cellular, explained
Push-to-talk over cellular, often shortened to PoC, is a two-way radio that sends its audio over LTE, 5G and Wi-Fi instead of a frequency you own. One button, one channel, everyone hears, with the carrier network as the range.
Short answer
What is push-to-talk over cellular?
A push-to-talk over cellular radio looks and behaves like a walkie-talkie: press the button, talk, release, and everyone on the channel hears you at once. The difference is how the audio travels. Instead of a radio frequency that reaches a few miles, it goes over the cellular networks and Wi-Fi as data, so the same radio works across a building, a city or the country wherever there is supported coverage. There is no repeater to install and no FCC license to hold, because the carriers already hold the spectrum.
How it works
What happens when you press the button
The radio has a SIM and a cellular modem, like a phone, but no dialer. When the button is pressed, the audio is sent as a data stream to the push-to-talk platform, which relays it instantly to everyone on the channel and to the dispatcher in the office. The platform we deploy is Zello. Channels are set up by the provider rather than programmed into each radio, so adding a person, moving a crew to a new channel or reaching a truck in another state is a change made remotely. Location travels the same way, which is how the dispatch map knows where everyone is.
The radio
A rugged handheld or vehicle unit with a cellular modem, a SIM and a push-to-talk button. Ours are Inrico and Telox Android radios running Zello.
The network
Audio and location travel as data over LTE, 5G and Wi-Fi. The carrier holds the license; you hold a SIM. Coverage follows the network rather than a tower you own.
The platform
Zello Work relays calls between radios, phones and dispatch, shows the location map and holds the channel structure, so changes are made remotely.
Where it helps
Where it differs from other radios
The practical differences from the alternatives, in one place.
Conventional UHF and VHF radios reach a few miles from a licensed repeater; PoC reaches wherever the carrier does
Consumer FRS walkie-talkies need no license but stop at the tree line; PoC needs no license and keeps going
Phones reach one person after dialing and ringing; PoC reaches the whole channel the instant the button is pressed
A licensed system needs a repeater, an antenna and a ten-year FCC license; PoC needs a SIM and coverage
Nextel Direct Connect did this on one proprietary network; modern PoC runs as an app over standard LTE, 5G and Wi-Fi
Where cellular is weak, PoC radios fall back to Wi-Fi, and an existing local radio system can be bridged for the gaps
Push-to-talk over cellular depends on supported cellular or Wi-Fi coverage where your people work. Coverage is wide-area rather than universal, and Integrated Radio confirms it against your specific sites and routes before quoting.
Questions
Questions about push-to-talk over cellular
What buyers ask when they first hear the term.
Is push-to-talk over cellular the same as Nextel Direct Connect?
It is the same idea, done on open foundations. Nextel delivered push-to-talk over its own iDEN network and the service died with that network in 2013. Modern PoC runs as an application over standard LTE, 5G and Wi-Fi, so it is not tied to one carrier's proprietary technology.
Do I need an FCC license?
No. The radios use the carrier networks, which already hold the spectrum licenses. There is no frequency to coordinate, nothing to file and no antenna to install.
What happens where there is no cell signal?
Where there is no supported cellular or Wi-Fi coverage, a PoC radio cannot pass traffic. That is why coverage is checked against your actual sites before anything is quoted, and why an existing local radio system can be bridged for known gaps.
Does it work indoors?
Usually. Supported radios use Wi-Fi as well as cellular, which helps inside warehouses, hotels, plants and other buildings with strong wireless coverage. Inside steel buildings we confirm signal on site.
How is it different from a walkie-talkie app on my phone?
It is the same technology. Zello, the platform we deploy, runs on phones and on purpose-built radios, and both can share a channel. The difference is the device: a radio is built around the button, survives the environment and cannot be distracted by other apps.
Is there a delay?
A well-engineered PoC call sets up in well under a second and sounds like a radio call. The audio is sensitive to network availability rather than bandwidth, which is why coverage matters more than speed.
What does it cost?
Managed Zello Core is $24.95 per user per month and Managed Zello Plus is $34.95, each including the managed Zello network, device management and a multi-carrier data plan. Radios start at $199, sold separately. The pricing guide has the detail.
Related
Where to go from here
The platform we deploy is Zello, run as Managed Zello. See business two-way radio for Zello on rugged radios, and Zello Dispatch Hub for the office. Core vs Plus sets the two plans side by side, and the online store lists every radio and rugged phone.
For the background, read what happened to Nextel and what nationwide coverage actually means. The FCC licensing guide and the pricing guide answer the two questions that usually come next.
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