Operative-technical sector, Berlin, January 10, 1977
The head of PKO / Fe OTS/043/77
Abteilug X
cooperation with the Cuban security forces
you are requested to inform the Cuban brother organ telegram that the OTS required for the completion of the art "2028.3" urgent following information:
first What Netzfrekuenz (50 Hz or 60 Hz), the appliance should be delivered?
second How are the bands will be discussed: 
with female or male voice? -which languages are required?
-digits and words which are desired?
The delivery of technology to the institution to a brother - made 2 months after receipt of this information.
Colonel Schmidt
On 24 January 1977 reported the liaison officer of the Stasi in Havana.
"The device is designed for HV reconnaissance determined Comrade Major Eddy Herrera gave me the definitive answer: 60 Hertz, feminine language for the bands, English language, numbers 1-0, words : atención final adios "
The technique was 2028.3 for the agents of the Cuban radio broadcasts information (DGI) is translated.
On 18.07.1974 also reported the OTS, the supply "of operational art to Cuba":
"You are requested to inform the Cuban brother institution, that the OTS in 1975, 2 appliances provide wird.Der 2028 guide price for 1 unit is 30,000 marks "
In the recording of a radio broadcast of the Cuban education:
http://cubanintelligence.com/
http://www.youtube.com/watch?v = Ezc5XGQ5jFs & feature = player_embedded