Ericsson DIALOG 4220 - Manual (Page 65)

65 Dialog 4220 Lite/Dialog 4222 Office
Other Useful Features
Hot line
Ask your system administrator if you require this function.
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.
Note: This function is only available in newer versions of the
exchange.
Direct Hot line
The same function 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.
Alarm extension
An extension can be programmed by your system administrator as
an Alarm extension. A call to an Alarm extension obtains automatic
Intrusion if the extension is busy. Up to seven calling parties may be
connected at the same time.
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.