BT 4600 Big Button Cordless Phone with Call Blocking. A practical digital cordless phone for the home with Nuisance Call Blocking powered by Truecall the BT4600 helps you protect your home from unwanted sales calls. The handset features extra-large buttons for ease of use and is capable of providing reliable range of up to 50 metres indoors and 300 metres outdoors you can enjoy calls in outstanding clarity throughout your home.. Call blocking made easy. The BT 4600 comes with BTs multi-award winning call blocking technology powered by TrueCall for complete protection against nuisance callers. Now with a dedicated call-block key you can instantly block numbers from incoming callers (up to 1,000 numbers can be added to the blocked call list). And with BT Premium Call Blocking feature youll never have to speak to another cold caller again as the phone will make unknown callers announce their name and play it back to you so you can decide whether or not to answer.. Do Not Disturb. And fo