Best guess is that you are talking about Tone Demonstation
Lift the handset.
Dial the Tone Demonstration feature access code.
Dial the tone identification code.
Do one of the following:
To exit, hang up.
To listen to another tone, dial another tone identification code
Tone Identification Codes
10 silence
11 dial tone
12 transfer dial tone
13 busy tone
14 do not disturb tone (special busy tone)
15 standard ringback tone
16 special ringback tone
17 reorder tone
18 conference tone
19 camp-on tone
20 override tone
21 interrupted dial tone
22 interrupted dial tone with message waiting tone
23 waiting tone
24 paging tone
25 dial tone with message waiting tone
26 data connect tone
27 extended second dial tone
28 feature active tone
29 confirmation tone
30 congestion tone
31 Channel Associated Signaling ( CAS) tone
33 ringer pitch adjust tone
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What's most important is that you realise ... There is no spoon.