Michael_N wrote:yes a dialer.
one of the reasons for using a dialer is that it skips nonexisting numbers very quikly.
There is no method of skipping a nonexistent number quickly. Many Telcos take up to 45 seconds to generate "this number does not exist". During the wait time, the caller (dialer, cell phone, VOIP, no difference) will receive a ring-tone and/or associated signal based on the policy of the Telco. There is no way around this, dialer or not, without access to the Telco records.
Even paying someone to "wash" your list will always have an error margin because numbers change. But that can greatly reduce your "bad number" dialing.
Most localities/governments state a minimum ring time for making calls. In the US I believe it's 15 seconds. Don't quote me, though.