AASTRA 4223 Professional for BusinessPhone User Guide - Manual (Page 128)

Installation
BusinessPhone — Dialog 4223 Professional / Dialog 3213 128
Install key panel
1 Connect cable
2 Attach key panel unit
3 Secure with screws
4 Install stand
When connecting one or two optional key panels to your telephone
the DBY 409 01 key panel may be used. No external power cables
are required for this key panel, as power is supplied from your
telephone.
However, if three or four key panels are to be connected, then the
DBY 409 02 optional key panel must be used for all key panels
connected to your telephone. Whereby, a 24 V a.c. power cable
must be attached to the first key panel connected to your
telephone to provide power to all key panels.
24 V a.c. connection
when more than two
key panels are used.
Connection must be to
the first key panel