Panasonic KX-TD500 System Reference Manual page 339

Operation (A) By dialing an extension number
1. Lift the handset or press the SP-PHONE button.
• You hear dial tone 1, 3, or 4.
2. Dial the other PBX's extension number.
• You hear ringback tone.
(B) By dialing a PBX code and an extension number
1. Lift the handset or press the SP-PHONE button.
• You hear dial tone 1, 3, or 4.
2. Dial the feature number for "TIE Trunk Access" (Default : 7).
• You hear dial tone 1.
3. Dial the PBX code of the destination PBX and then the extension
number of your destination party.
• You hear ringback tone.
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