when a user performs a blind transfer or a semi-attended transfer, and the transfer recipient doesn't answer, the call will be transferred back to the user, but the user sees the only the external CLI in phone display or Linkus APP; it could be useful that the pbx adds a "label" in front of the CLI, with the extexnsion number to which the call was transferred;
- ext. 1000 makes an external call transfer (CLI 0547385611) to ext. 1001
- ext. 1001 doesn't answer the call
- the call comes back to ext. 1000 and the pbx sends as Caller ID "1001>>0547385611"