PTT Sofia :

 

no recordings available

 

see here a verification letter (with PPC) from the collection of Michael Kunze (1992)
...and here a slightly different version (Andreas Ibold)
this one looks even more professional (Dieter Pohlmann, 1992)

------------------------------------------------------------

 

Callsigns:
LZA *
LZC *
LZD **
LZE *
LZF **
LZG *
LZH *
LZI **
LZJ *
LZK
LZN **
LZP *
LZQ *
LZS
LZT
LZU **

 

Frequencies Voice:
8055
8096
8100
10915
15730

 

Frequencies Morse Telegraphy:
20045

 

Frequencies Radioteletype:
4813
4841
5045
5102
5125
5442
5715
5766
5835
6840
6960
7385
7585
7948
7975
8055
8107
8171
9105
9277
9472
9855
9885
10171
11315
11502
12315
12325
13400
13453
13935
14474
14479.9
14970
15615
15622
15715
16110
16410
18210
18555
19770

 

Systems used:
50 Bd
75 Bd