A button adds the usual dialing rules, and each rule can show its own caller ID.
Setting up dialing rules for North America is the same every time, so now it is one button.
What the button adds
People dial the same number in several ways: ten digits, eleven with the 1 in front, or the full international form. All of them should work, and all of them should reach the provider written the way that provider expects.
The button writes the rules that do that. Before, each had to be typed in by hand, with a prefix, a digit count and what to strip, and one typo meant calls that would not go out.
After that the rules are ordinary rules. Edit them, reorder them, delete the ones you do not want.
Caller ID per rule
Each rule can show its own caller ID. That covers the office that wants the main line shown on most calls and a direct line on others, or a business with two names behind one phone system.
If a rule has none, the provider's own setting is used, as before.
Rules read top to bottom
The first rule that matches a dialed number decides. So the order matters, and the page shows it the way the system reads it. A specific rule goes above a general one.
Why this is in the product at all
Because it is the first thing every new install needs, and the first thing people get wrong. A phone system that cannot call out on day one because of a missing rule makes a poor first impression. One button, and it can.