Anonymous call rejection is a calling feature based on caller ID. Anonymous Call Rejection lets you refuse incoming calls from people who have blocked their phone number and name, which is something a lot of telemarketers do, so if you're fed up of your phone ringing at unwanted time, this might be a good option. Instead of being interrupted, your caller will be redirected to an announcement letting them know that you don't accept calls where the caller's identity has been masked. It is often free with caller ID on landline

If you're calling someone who has Anonymous Call Rejection service, and you block your number from being shown, your call will be diverted to a recorded message telling you that the called party does not accept blocked calls and to unblock before calling or the call won't go through.

Selective Call Rejection allows you to reject calls that meet your predefined criteria like based on caller id, time, country etc.