220.127.116.11.1 Pans. The form of test transmission should be as follows:
a) the identification of the station being called;
b) the aircraft identification;
c) the words “RADIO CHECK”;
d) the frequency being used.
18.104.22.168.2 PANS. The reply to a test transmission should be as follows:
a) the identification of the aircraft;
b) the identification of the aeronautical station replying;
c) information regarding the readability of the aircraft transmission.
22.214.171.124.3 PANS. The test transmission and reply thereto should be recorded at the aeronautical station.
126.96.36.199.4 PANS. When the tests are made, the following readability scale should be used:
2 Readable now and then
3 Readable but with difficulty
5 Perfectly readable
Source: ICAO Annex 10.2