Definition
A half-duplex group communication model in which a user presses a button to transmit to an entire talk group and releases it to listen, delivered over dedicated trunked radio infrastructure or, increasingly, commercial cellular networks as push-to-talk-over-cellular.
Key Points
- Operates half-duplex, meaning only one talk group member transmits at a time while others listen, rather than the full-duplex simultaneous two-way communication a standard phone call provides
- Traditionally delivered over dedicated trunked radio infrastructure such as TETRA, giving an organization direct control over its own group communication capability rather than depending on commercial network availability
- Increasingly offered as push-to-talk-over-cellular, delivering the same group communication user experience over commercial mobile network data connections rather than requiring dedicated radio infrastructure
- The cellular-delivered variant trades dedicated infrastructure control for commercial network ubiquity and lower deployment cost, since it can reach anywhere commercial cellular coverage exists without an organization needing to build or maintain its own radio network
- Group communication latency — how quickly a transmission reaches all listening talk group members — is a key usability factor, with dedicated trunked radio traditionally offering more consistent latency than early cellular-delivered implementations, though this gap has narrowed considerably with modern cellular network performance
Concept
A PTT user's transmission reaches every member of their talk group simultaneously the moment they press and hold the transmit button, with the underlying infrastructure — whether dedicated trunked radio or a cellular data connection — responsible for delivering that transmission to all listening group members with acceptably low latency. The user experience of pressing to talk and releasing to listen remains consistent regardless of which underlying infrastructure actually carries the communication.
Explainer
The shift toward push-to-talk-over-cellular reflects a straightforward cost and coverage tradeoff against dedicated radio infrastructure like TETRA — an organization can gain PTT group communication capability anywhere commercial cellular coverage already reaches without building or maintaining its own radio network, at the cost of depending on that commercial network's own availability and priority handling during high-demand periods rather than controlling dedicated infrastructure directly. This is precisely why the choice between dedicated trunked radio and cellular-delivered PTT tracks closely with how much an organization values infrastructure independence versus deployment simplicity and cost: public safety and defense organizations with mission-critical communication requirements have historically favored dedicated infrastructure specifically because it removes dependency on commercial network conditions, while organizations with less safety-critical coordination needs increasingly find cellular-delivered PTT's lower cost and broader reach the more practical choice. For CE verticals, PTT capability — whichever infrastructure delivers it — is directly relevant to field operations coordination across mining, energy, and logistics contexts where group communication among dispersed personnel matters more than the point-to-point call model conventional telephony provides.
Cite this entry
Push-to-Talk. ConnectedEarth Knowledge Base. https://connectedearth.space/knowledge-base/push-to-talk/ (updated 13 September 2026).