Panasonic KX-TDA0490 Getting Started page 62

B2 Programming for the Extension Number Method
Step 8
Assign the routing information to route calls to the remote PBX:
In the Leading Number box, type 3 (for the Chicago office extensions), 6 (for the Chicago office fax
extensions), and 93 (for Chicago office PSTN access).
Note
Do not set any value in the Own PBX Code box.
After the above step, follow the procedure in "4.1 Programming the PBX in the Los Angeles Office",
starting from step 8.
62 Getting Started