AASTRA 4225 for MX-ONE Telephony Switch - Manual (Page 92)

Other Useful features
Dialog 4223 Professional/Dialog 4225 Vision 92
Hot Line
This feature is programmed by your system administrator.
Delayed Hot Line
When the handset of the delayed Hot Line phone is lifted or when the
Line key is pressed, a timer is started. If no digit is pressed before time
out, a call is automatically generated to a specific extension or external
line. If a digit is pressed before time out the phone works as an ordinary
phone.
Direct Hot Line
The same feature as described above, but without a delay. Only Hot
Line calls can be placed from this line. To be used e.g. as alarm phone,
door phone etc.
Emergency mode
In the event of an emergency the operator can set the exchange into
Emergency mode, during which only preprogrammed extensions are
permitted to make calls. If your extension is not assigned with this
category and you try to make a call, you will not receive a dial tone.