VTech CS1501 DECT Digital Cordless Phone with Call Block,

[Nuisance Call Blocker] - Avoid nuisance and unwanted calls. VTech's call blocker feature allows you to block nuisance calls and calls from unknown numbers. Block up to 60 blacklisted numbers. [3-way conference] - Handset call transfer and intercom allows multiple users to get in on the conversation simultaneously.

eBay