Backatcha Bandit said:
When were bi-directional data links first utilised in commercial avionics? I thought you were the expert.
My previous link mentions it (1997) for a start.
Here's a leaflet about it. Some nice colourful graphics so you won't have to bother actually reading it.
What do you class as a bi-directional data link?
The first link you posted, each article was all of 1 paragraph long and states
controller / pilot data link
What controller?
The article doesn't specify. Microcontrollers / processors are fitted in lots of electronic equipment. So for example the engine fire warning goes off. The pilot responds by pressing the fire extinguisher button. This is a bi directional data system. The aircraft tells the pilot of a problem, the pilot tells the aircraft what to do about it.
A radio is a bi-directional data system. The air traffic controller tells the pilot to turn to a specific heading or climb to a certain height. The pilot also relays data back to ATC using the radio.
I can't check your rockwellcollins link as the site is not responding.
Wouldbe, you'll have to forgive me, but (dispite your Btec) I really am starting to think that you don't know what the fuck you are talking about.
Can I hear the data when I use VOIP? How about when I pick up the phone that is on the same line as my DSL connection?
I find this rich comming from someone who apparently doesn't know how a telephone or transceiver works let alone anything as complicated as avionics so let me fill you in.
A telephone (landline) system is a duplex system i.e. both callers can talk at the same time and you can both hear each other talking over the other party. DSL works by modulating the PC data onto the phone line so the PC can be sending data to the net while voice data is coming the other way. The signals do not interfere with each other due to the micro filter you plug into the phone socket.
A transceiver system is a simlex system i.e. you can
either transmit or receive hence the need to say 'over' when you have finished to let the other party know that they can talk. Receiver sensitivity is about 10mW. Transmitter power is in the order of 10W - 50W. What do you think would happen if you tried to transmit and receive at the same time? That's right you burn out the receiver stage because you have overloaded it with a signal some 1000 times higher that it was designed to handle.
So this mystery bidirectional data that could use the VHF / UHF radio system
now has to have the abiltity to not only detect when the pilot / ATC are talking so that possibly vital voice data is lost, but also has to be able to predict when the piolt / ATC are about to transmit for the same reason.
You also could not have 2 separate antenna for transmit and receive as the signal strength from the transmitter would block out the much weaker signals from the ground.