View source for Push-to-talk

{{short description|Protocol in half-duplex telecommunication devices}}
{{distinguish|Click-to-call}}
{{more citations needed|date=February 2013}}
'''Push-to-talk''' ('''PTT'''), also known as '''press-to-transmit''', is a method of having conversations or talking on [[duplex (telecommunications)|half-duplex]] communication lines, including [[two-way radio]], using a [[Switch#Biased switches|momentary button]] to switch from voice reception mode to transmit mode.

[[File:Citizens Band CB Cobra 18 WX ST II with microphone.jpeg|thumb|upright|[[CB radio]] with push-to-talk microphone switch]]

== History==
For example, an [[air traffic controller]] usually supervises several aircraft and talks on one radio frequency to all of them. Those under the same frequency can hear others' transmissions while using [[procedure word]]s such as "break", "break break" to separate order during the conversation (ICAO doc 9432). In doing so, they are aware of each other's actions and intentions. Unlike in a [[conference call]], they do not hear background noise from the ones who are not speaking. Similar considerations apply to [[police radio]], the use of [[business band]] radios on [[construction]] sites, and other scenarios requiring coordination of several parties. [[Citizens Band]] is another example of classic push-to-talk operation.

The PTT switch is most commonly located on the radio's handheld microphone, or for small hand-held radios, directly on the radio. For heavy radio users, a PTT foot switch may be used, and also can be combined with either a boom-mounted microphone or a headset with integrated microphone.

Less commonly, a separate hand-held PTT switch may be used. This type of switch was historically called a ''pressel''.{{cn|date=March 2024}}

In situations where a user may be too busy to handle a talk switch, [[voice operated switch]]es are sometimes employed.  Some systems use [[PTT ID]] to identify the speaker.

== Mobile phones ==

''[[PoC radio|Push-to-talk over cellular]]'' ('''PTToC''') is a service option for a [[cellular phone]] network that enables subscribers to use their phones as [[walkie-talkies]] with unlimited range. A typical push-to-talk connection connects almost instantly. A significant advantage of PTT is the ability for a single person to reach an active talk group with a single button press; users don't need to make several [[telephone call]]s to coordinate with a group.

Push-to-talk cellular calls similarly provide [[half-duplex]] communications – while one person transmits, the other(s) receive. This combines the operational advantages of PTT with the interference resistance and other virtues of mobile phones. Manufacturers of ('''POC''' or '''PoC''') hardware include ToooAir<ref>Sharon O'Keeffe. {{cite web |date=November 28, 2017 |title=ToooAir Launches a Push to Talk Over Cellular Device |url=https://www.farmonline.com.au/story/5085725/two-way-style-powered-by-telstra-network/ |website=www.farmonline.com.au}}</ref> and [[Hytera|Hytera US Inc.]]<ref>Jena Tesse Fox. {{cite web |date=May 26, 2022 |title=Hytera introduces the PNC360S series of PoC devices |url=https://www.hotelmanagement.net/tech/hytera-us-launches-new-communications-device |magazine=Hotel Management}}</ref>

Mobile push-to-talk services, offered by some mobile carriers directly as well as by independent companies, adds PTT functionality to smartphones and specialized mobile handsets (hand portable and mobile/base station PTT Radio Terminals).  In addition to mobile handsets, some services also work on a laptop, desktop, and tablet computers.

== Smartphone and computer apps ==

Recent development in PTT communications is the appearance of [[Mobile app|app]]s on [[smartphone]]s, some of which can function on multiple platforms. Wireless carrier-grade PTT systems have adapted to and adopted the smartphone platform by providing downloadable apps that support their PTT systems across many mobile platforms. Over-the-top (OTT) applications do not depend on a specific carrier or type of communication network,<ref>{{Cite web |date=2022-05-10 |title=Push-to-Talk Services - Orion |url=https://www.orionlabs.io/push-to-talk-services/ |access-date=2024-03-03 |website=www.orionlabs.io |language=en-US}}</ref> and may be slower than carrier implementations.

==See also==
* {{annotated link|OMA Instant Messaging and Presence Service}}
* {{annotated link|Push-to-type operation}}
* {{annotated link|Click-to-call}}

==References==

{{reflist}}
*[http://www.motorola.com/content.jsp?globalObjectId=2647-4398 Push-to-Talk over Cellular Consortium Phase 2 Specifications and Documentation]
*[http://www.openmobilealliance.org/technical/release_program/docs/poc/v2_0-20080421-c/oma-ad-poc-v2_0-20080226-c.pdf Open Mobile Alliance - Push to talk over Cellular (PoC) - Architecture Candidate Version 2.0 – 26 February 2008]

{{Mobile telecommunications standards}}
{{Two-way radio}}
{{Telecommunications}}

{{DEFAULTSORT:Push-To-Talk}}
[[Category:IMS services]]