Configuration of the ZDD-1 (used with ICX-AlphaCom)
From Zenitel Wiki
To use the Zenitel Display Door intercom (ZDD-1) with ICX AlphaCom it must be in SIP mode, and a SIP Station license is required
To use the Zenitel Display Door intercom (ZDD-1) with ICX AlphaCom it must be in SIP mode, and a SIP Station license is required