Outbound lists · practice · 12 min full read
List penetration is the default. The dialer tries the first phone on every record, then the next phone on a later pass. Vertical dialing stays with one contact and moves across that contact's numbers before it moves on.
The community article's wording is easy to twist: it says the physical direction of list penetration is vertical, while the industry phrase vertical dialing means walking numbers across a record. Use the article's definitions, not the compass words. A final disposition stops every number on the record in either mode.