Push to talk
Push-to-talk (abbreviation PTT , English for pressures to speak ) generally refers to the button for switching from reception to transmission in radio devices .
application
In contrast to the conventional telephone , where the simultaneous speaking of both participants i. A. is technically possible ( full duplex ), in radiotelephony traffic it is usually only possible for the participants to speak to one another ( half duplex ). In these cases, the PTT button is required to switch the transmitter on in order to start the voice transmission.
Only after pressing the PTT button is the (voice) signal present at the microphone input transmitted by the transmitter of the radio device via the antenna . If you want to stop sending, you have to release the button. During the transmission, the receiving part of the radio device is usually switched off, since the reception of the own transmission is not desired.
technical realization
In the case of handheld radios , the button is usually located directly on the device. For mobile stations with a handheld microphone, the button on the microphone has become common. In the case of base stations with a standing microphone, the button is usually located in the base of the microphone.
Furthermore, the button can also be designed as a foot switch. So the operator has both hands free.
Alternatives
As an alternative to the PTT button, the transmit / receive switchover can also be done voice -controlled with a so-called VOX control ( Voice Operated Exchange ; the double meaning of the Latin "Vox" for "voice" is obviously intended).
See also
Based on the PTT button on radios and the reception of the transmission on several devices, various techniques were also called PTT:
- Push-to-Talk over Cellular , PTT for mobile phones