The W52 base station can have 4 handsets assigned to it, and the W60 can have 8 handsets assigned to it. This KB goes over how to set up the additional lines required in the portal for the handsets to ring correctly. 

In the Portal

1. Log into the portal, locate the user who will be assigned to the first line, and add the base station's MAC address to the users' phones. 
   
2. Navigate to the user profile that will use the second handset. Ensure they have a free extension available. The Phones tab should look like the below image. 
   
3. Navigate to Inventory -> Phone Hardware.
4. Locate the first user's extension and click the edit button. Under line 2, add the second handset extension. 
   
5. Save and Resync the phone. 
6. Ensure each handset is registered to the correct base and assigned to the correct line on the base. The handset's screen will indicate which line it is assigned to.