NEC Univerge SV9100 - Page 427

427
 Receive the new CO/PBX dial tone.
3. Dial the desired number.
To use the Drop Key feature from a single line telephone with a CO/PBX call in progress:
1. Hookflash.
2. Receive internal dial tone.
3. Dial the Service Code (Program 11-12-59, default not assigned).
4. Receive the new CO/PBX dial tone.
5. Dial the desired number.