Push-to-talk latency isn’t a problem in the “it might replace SMS” scenario the mobile industry once envisaged for it, but it is in an emergency. The classic example the Armed Forces give is to imagine a commander who has a team of snipers on a roof pointing at a target. He gives the command: “Don’t shoot”. Unfortunately, in a cellular, IP based device, it takes a fraction of a second for the app to fire up and make a connection – a fraction of a second which is just long enough for the word “Don’t” to fail to make it into the message.
In my military training for the communications troops more than 35 years ago, we were drilled to "Think, Push, Breathe, Talk", because analog equipment has warmup latency, and besides, one would easily tend to unconsciously talk already while pushing the talk button.
If anything, it would be EASIER for digital equipment to work around this, analogous to how shutter buttons in digital cameras work: Run the microphone in always on mode and keep a short ring buffer of the audio prior to the button push.
Apparently delaying the message is rather hard for regular solutions. I've worked on a project where delaying the message (and playing a few tones first) was sufficiently hard that one of the reasons we got that project in the first place is because we actually could.
Thanks for the reference. I don't doubt that push-to-talk latency is a problem but I'm afraid my common sense still prevents me from believing that particular example, despite the Register's quotation of "the Armed Forces".
Push-to-talk latency isn’t a problem in the “it might replace SMS” scenario the mobile industry once envisaged for it, but it is in an emergency. The classic example the Armed Forces give is to imagine a commander who has a team of snipers on a roof pointing at a target. He gives the command: “Don’t shoot”. Unfortunately, in a cellular, IP based device, it takes a fraction of a second for the app to fire up and make a connection – a fraction of a second which is just long enough for the word “Don’t” to fail to make it into the message.