Is there an addition to a telephone that requires a code to allow a call to come through?

Question

This would block any calls from persons who do not have a personal pass-code.

Answer 1

I know its possible because I've seen some businesses you pin numbers to access their phones and people, but you probably need somesort of pbx switch.

Answer 2

Selective incoming for local use would be pricey...and probably be available via a commercial service.

But you can get a 800 service number from an array of LD carries that require a PIN to complete the call and let it ring through.

You will pay the charges of about 5,7,10 cents a min.

Locals can call as well but you will still pay a pmc.