AASTRA 4222 Office for MX-ONE (TSE) User Guide EN - Manual (Page 12)

Description
Dialog 4220 Lite/Dialog 4222 Office 12
Ring signals
Three different ring signals inform you about the type of the incoming
call. The signals shown in this section are the most used signals
worldwide. Many markets use signals that are adapted for the local
standards. If you get a signal that is not described or you cannot
identify, ask your system administrator.
Internal ring signal
External ring signal
Recall signal
(Callback reminder)