Attention: Not all telephony operators and the various countries use the same prefix to precede the number to make a call "anonymous", always try first that actually the prefix to work correctly. Some operators then use restrictions in this regard, disabling the anonymous call, restrictions which can be removed by calling your operator. For example, in India, this service can be enabled but is disabled by default to legal restrictions. Even if you want to enable it, then there are a lot of lega