listen to the RTTY test tape (rb, 1984) 
just in case you have no decoder
at hand ;-)
a PPC confirming the RTTY circuit, AFTN (flight data) to Tehran
(rb, 1985)
different PPC, for the air/ground service (Michael Oexner, 1991)
------------------------------------------------------------
Callsigns:
YAV **
Frequencies Voice:
2966
3446
3467
5601
5658
6547
6624
10009
10018
13288
13312
13336
Frequencies Morse Telegraphy:
4570
6925
Frequencies Radioteletype:
4622
5010
5266
7905
9052
10532
11065
Systems used:
50 Bd