AASTRA 4425 IP Vision (SIP) for MX-ONE User Guide - Manual (Page 38)

39 Dialog 4425 IP Vision
Outgoing Calls
Handsfree
With the handset on hook: z
Call Enter the number and press to dial.
You are connected via the loudspeaker and microphone.
í
Press to terminate a handsfree call.
SOS calls (Emergency calls)
When your phone is logged on z
Dial the SOS number.