Figure 8-36 System Data 11-02: Extension Numbering - NEC Univerge SV9100 Manual

Issue 2.0
After one port in a block of two is used by a VoIP station, the
remaining port can be used only for another VoIP Extension.

Figure 8-36 System Data 11-02: Extension Numbering

4. This step is optional.
To enable Key data and other station feature programming (before IP
Phone is brought online) the extensions must be identified as IP
Phones. Once checked in the IP Phone List in PCPro, the extensions
are available for selection in Program 15 and other station related
8-64 IP Multiline Station (SIP)