Hello ​@bgrimshaw,

A Digital Line Unlimited (DLU) is a full-featured user license, while an Additional Local Number (ALN) is a low-cost, standalone phone number. The significant price difference you see on your bill is because the DLU gives a single user full access to the platform, including unlimited domestic calling and all communication tools. The ALN is simply an add-on for a specific purpose.  

Here's the key breakdown:

• Digital Line Unlimited: You would get this for a new employee who needs their own personal line to make and receive unlimited calls, send texts, and use the mobile and desktop apps.  

• Additional Local Number: You would get this to add a new number for a department, a marketing campaign, or to give a second inbound number to an existing user.  

As you suspected, an ALN on its own cannot make outbound calls. Outbound calling is a core feature of the DLU license. An existing user with a DLU can use an ALN as their outbound caller ID, but the call itself is still processed through their main DLU license.