*** Answering a msg posted in area ECHO_PM0 (GEcho PM for Jay Hanig).
 JH>> My understanding was that it was most definitely a one way device.
 JH>> Sometimes the message would get stuck in the tube and the instructor
 JH>> would have to hold his end out into the slipstream to be sure the
 JH>> student was getting the message.
 HH> I always wondered why my primary instructor wore a whistle around his 
neck
 HH> during flights.  One very dense day, I found out!!!
You had dense days?
Jay
--- GoldED/386 2.50+
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