This is interesting its a device to stop cold callers. Ironically it was invented by two ex telemarketers. The device is called TrueCall and it works by downloading information on commercial and scam numbers form the internet and preventing them from getting in contact with you. It can also block calls from people that you don’t want to speak to. The system intercepts all calls and if it recognises them as a friend or family of the user it lets them through as normal. However, if the callers number is identified as a telemarketer or nuisance caller the device answers it with an automated message and the phone does not ring at all. Its not cheap at £99 but it looks like it could a solution to unwanted sales calls.