A system and method for maintaining a grey list for controlling incoming calls from numbers
on a telephone network. Information associated with previous calls received by the
telephone is stored in the form of a grey list. The stored information includes an indication of
whether each of the previously received calls passed a previous challenge. Based on the
stored information, when an incoming call is received, a determination is made whether the
incoming call corresponds to a call that passed a previous challenge. The incoming call …

A system and method for maintaining a grey list for con trolling incoming calls from numbers
on a telephone net work. Information associated with previous calls received by the
telephone is stored in the form of a grey list. The stored information includes an indication of
whether each of the previously received calls passed a previous challenge. Based on the
stored information, when an incoming call is received, a determination is made whether the
incoming call corresponds to a call that passed a previous challenge. The incoming call …