There are several machines, services and software options available that block, or screen, unwanted calls from telemarketers. Panasonic builds a call-blocking feature into most of its answering machine units, while Privacy Corps sells machines that claim to block telemarketing calls and remove a user's number from calling lists.
Telephone companies provide telemarketing screening and blocking services, such as AT&T's Privacy Manager, while third-party services, including Nomorobo and Phone.com, monitor incoming calls and discard telemarketers. For cell phones, both iPhone and Android platforms have built-in features that only require adjustment of the phone's call settings. On iPhones, a Do Not Disturb setting accepts calls only from numbers on the phone's favorites list, while on Android models, this can be accomplished by adjusting the blocking mode settings.