PRO Call Blocker Version 1.0 By Hqtelecom Compatible all major local exchange carriers and imcumbent companies including (but not limited to) the following: AT&T, CenturyLink, Comcast, FairPoint, Frontier Communications, Hawaiian Telcom, Verizon, Windstream. Compatible with all major VoIP providers including: MagicJack, Comcast, AT&T U-verse, Verizon FIOS, Ooma, Vonage, and many others Large storage - Stores up to 1,500 telephone and fax numbers in blacklist memory Easy to Use - Simply press a button to store telephone and fax numbers in "Blacklist"