AASTRA 4225 for MX-ONE Telephony Switch - Manual (Page 58)

During Calls
Dialog 4223 Professional/Dialog 4225 Vision 58
Dialing during a connected call
When calling interactive teleservices, e.g. telephone banks, you need to
use Dual Tone Multi Frequency (DTMF) signals. If your exchange has
not been programmed to automatically convert your entered digits into
DTMF signals, you need to activate the feature during the call.
During an ongoing call:
Tones
z
Press (see display) and dial the requested digits.
Entered digits are transmitted as DTMF signals.
Notes:
You can also press 9
and dial the required digits.
Finland, press
1
and dial the required digits.