AASTRA 4224 Operator for MX-ONE User Guide - Manual (Page 90)

Installation
Dialog 4224 Operator 90
Installation
Install cables
You can put the cable to the handset in the notch underneath the
terminal. The cable to the exchange has to be plugged in “LINE”
and the handset cable has to be plugged in “HANDSET”.
Change cables
To remove a cable, use a screwdriver to unlock the stop.
Handset cable to the left Handset cable to the right