Panasonic NS1000 Manual page 179

Trunk calls via Remote (Slave) Units.
An extension user can access trunks connected to remote units thus reducing call costs.
An International call can be reduced to Local Call charges.
Paris
PTSN
Branch Office
Ext.1101
Through ARS programming, outgoing calls can be routed so as to reduce call charges.
The Master unit has the ARS tables (System Common Setting) and controls all outgoing
calls.
2-2. Main 'One-Look' Features
Ext.1001
One-look Networking
Internal Company Call
Head Office
(No charge)
Hamburg
PTSN
Local Call
Total call charges
can be reduced.