How the Russian PAR (RSL) works vs. "normal" PAR
In the East, the pilot reports flight passing set points (1000 m, 600 m, further NDB, closer NDB, etc.), and RSL controller confirms, he is giving the distance to the runway threshold. RSL controller, in principle, is active only in fixed locations, but also whenever the pilot deviates from the axis of the runway or in a vertical plane - from the approach path. Then he gives the command, eg "5 degrees to the left" or "reduce by half the descent." Each time the pilot shall acknowledge receipt of this command with his height AGL.
In turn, according to NATO procedures "Talk down" is done. Precision approach radar controller (equivalent to a RSL controller) presents a continuous monologue, giving the amendment or affirming the movement of aircraft at a fixed path approach. By the way, precision approach radar controller did not say "five degrees to the right" only "course 265" if the course is 260 degrees belt. However, in the continuous chatter of the controller cannot be interrupted by the pilot, so there is no read back or confirmation. Precision approach radar controller knows that the pilot can hear him, because he sees whether the pilot performs his command.
Source:
http://translate.google.pl/#pl|en|http%3A%2F%2Fwww.samoloty.pl%2Findex.php%2Fartykuly-lotnicze%2F5061-analiza-przyczyn-katastrofy-tu-154m.%0A%0A
(much more information available there)