There are four categories of PTT applications, which are differentiated by the type of vendor offering them.
Carrier-grade PTT applications
As the name states, these solutions are offered by the carrier. Since a carrier is in most cases the network provider and often the provider of mobile phones or tablets, it is logical that most carriers also offer a PTT solution, making them a one-stop-shop. In the US, except for T-mobile, all carriers offer a carrier-grade PTT app. Due to the direct network integration, the carrier-grade solution promises a higher Quality of Service (QoS) as traffic of PTT apps and others can be prioritized which is an advantage during poor network coverage or within saturated networks. Nevertheless, both Verizon and AT&T offer traffic management solutions to their customers which would allow the customer to prioritize the PTT app of choice. Carrier-grade PTT apps are also usually able to offer a convenient package solution including very low costs due to low cost feature phone integrations like flip phones, PTT only data packages, and overall bundle prices. Also there are some post service support advantages, such as having just one bill and a single point of contact available 24/7 to provide solution support.
Over-the-top (OTT) PTT applications
Over-the-top in this case means that the PTT solution is a layer over the general mobile phone provider network which directly describes its main advantage over the carrier-grade solution. OTT PTT apps are carrier agnostic and can work on any data network which is relevant if in certain areas the network provider has bad reception or for cross-border operations.
There is a multitude of different OTT PTT apps with different offerings, starting from a freemium model to highly sophisticated and use case specific solutions, more tailored than the more general carrier-graded offerings.
White labeled PTT applications
White labeled versions are usually versions of OTT PTT apps, customized for small to medium sized communication solution providers. These solutions offer direct support, customizations and other value added benefits to justify their place in the market.
Mission Critical Push-To-Talk (MCPTT) applications
First responders worldwide are slowly moving over to PTT over LTE solutions. This has led to the term Mission Critical PTT (MCPTT) applications in opposition to commercially used but still business critical PTT apps. ESN in UK and FirstNet in US are just two examples of such networks
For more guidance on implementing PPT apps, download the complete Whitepaper for free!