Panasonic DBS Section 540 Reference Manual page 105

Network Feature Operation
3. Complete the call and replace the handset.
Related Programming
• FF1 (System): Extension Class of Service Setting
• FF3 (Extension): Extension Class of Service Assignment
DBS-2.3/9.2-540
• If no trunks are available "NET BUSY GN" displays on your phone.
The FF key LED or EXT LED goes off.
T1 Networking - Revised April 2000
Extension to Network Extension Calling
Page 105