What is an "ATR" switch on an audioselectpanel
 

Hi,

The following question is still unanswered in some other forums It's not my personal question but I'm still wondering what the answer is. Mabe somebody overhere has clue?
You can find the disccusion on www.sjap.nl.
You can find a picture of the switch on: www.sjap.nl/050102_170955.jpg

in our 737-300 and 737-500 we have a strange channel button on our communication panel. the button's description shows the letters ATR, and it has its own volume control, just as the INT, PA, or the VHF buttons.
can anybody tell me what ATR means as no mechanic knows and even the manuals can't tell me.
is it something you usually use for HF communication as we don't have any HF sets installed any more on board of our a/c? i have a picture of this button, but as far as i can see i cannot put it in this forum.

Here is a guess...

ATR - Airbourne Telecommunications Receiver??

So you can use the headset & mic as a telephone whilst airbourne, turns off all other tx & rx.

However I could be a mile wide of reality (not unusual!)

Only edited this 10 times!