TelPal Landline Call Blocker For Landline Phones with Caller ID Display, Dual Signal FSK/DTMF, 1500 Number Capacity - Block Hidden Numbers, Telemarketer Calls, Nuisance Calls This is the latest version Telephone Call Blocker with hidden or unavailable call numbers can be blocked. And there is no fees to use it; Manual also have been updated to a improved one with better English directed. Block up to 1,500 individual phone numbers ( including incoming and outgoing calls ), prefixes and up to 10 area codes. One-touch blacklist function;very easy to operate even without manual; Better set the call blocker in-line (connected directly to phone, then to phone line); Though it also can be set up parallel with the phone to work, but some phone systems doesnt work. Permanent storage of the numbers in the blacklist even power is off or telephone line is plugged out. No need battery;Notice: It can work with almost all single line telephones, but not for VOIP Phones, Two Line Phones, Bright House Phones and AT&T Phones; If you found some numbers are blocked but you didnt mean to, check your Blacklist please, and delete those numbers which like area or prefix numbers, because they are the same