Telephone Caller ID

How about a mention of the make and model here. So, we can check out units we may like to know more about.
On my cellphone I use Zoner AntiVirus. It does call blocking and antivirus work. Had it for a few years works well.

Nigel's device must be masking the first ring signal so it can read the caller id before allowing any indication that a call is coming in.

ak

It sounds like you'll need a switcher and a monitor. When one line rings, that Call Display data appears on the screen while the other line remains available. As crutschow pointed out, a black list box is best to stop those pesky callers, much like an incoming call restrictor I've seen advertised with Weeder Technologies.

Telemarketers will not talk to an answering machine. LOL. I put an answering machine on my home phone when it rings and answers if the phone goes CLICK it know it was a telemarketer. LOL. I tell family and friends to say something so I know who you are then I will answer the phone so don't hand up just hang on a few seconds give me time to answer the phone.