the function of the ptt button on a two-way radio is to simultaneously receive.
the function of the ptt button on a two-way radio is to simultaneously receive.
what is the function of the ptt button on a two-way radio?
simultaneously receive
section::::nokia 6230i.:push to talk (ptt).









































the nokia 6230i features push to talk (ptt). push to talk (ptt) functions as a two-way radio. the ptt option is available only if enabled by the service provider.









































section::::nokia 6230i.:extra applications.
nokia 6230
when mission control (in houston, texas) wanted to talk to astronauts, the capsule communicator (capcom) pushed a button (push-to-talk, or ptt) that turned on the transmitter, then spoke, then released the button. when the transmitter is local, this is easy to arrange - the transmitter is connected directly to the ptt button. but to stay in continuous contact with the astronauts as they orbit the earth, or travel to the moon, nasa had to use tracking stations all around the world, switching from one station to the next as needed. to get the voice signal to the remote transmitter, dedicated telephone lines connected these stations to houston. nasa could either build a parallel system for operating the transmitters - one line to carry the audio and another to carry the control signal for the ptt button (out-of-band signalling), or combine these two systems together, using audio tones to turn the transmitter on and off. since dedicated phone lines were a very expensive measure at the time, nasa chose the use of tones to reduce the operating cost of the network. the same system was used in project gemini and was still in use with half duplex uhf space shuttle communications for transmitter rf keying.
quindar tones