66
Disconnect Supervision: Polarity Reversal / Clear Forwarding
Some Central Of
fi
ce switches signal the unit when the remote party in an outside call has
disconnected from the line. For example, if an outside call is placed on hold and during that time
the outside party hangs up, the system will know to release the line. The IPS supports two types
of signaling. With Clear Forward signaling, the Central Of
fi
ce removes the battery feed from
the Tips and Ring lines to signal that the remote party has disconnected. With Polarity Reversal
signaling, the Central of
fi
ce reverses the polarity of the Tip and Ring signals to inform the unit
when a connection has been completed and when it has been disconnected. If a disconnect signal
is detected during an outside line conversation, the extension hears special tone (on for 1 second,
then 2 brief beeps, then the system dial tone) to indicate that the call has been disconnected.
If you are being inappropriately disconnected from outside calls, disable both of these
parameters.
7844
To enable Polarity Reversal detection:
In programming mode, enter “7844”.
Pause for con
fi
rmation tone. Hang up or continue with programming.
To disable Polarity Reversal detection:
In programming mode, enter “7845”.
Pause for con
fi
rmation tone. Hang up or continue with programming.
7845
When Polarity Reversal detection is enabled, the IPS software will only store the details of an
outgoing call into Call History memory if the
fi
rst polarity reversal is received, indicating that the
connection to the called party is made. Thus if an outgoing call is made and the called phone rings
for longer than 20 seconds but never answers, the call is not recorded.
7820
To enable Clear Forward Detection
In programming mode, enter “7820”. Pause for con
fi
rmation tone.
Hang up or continue with programming..
Central Offi
ce Lines – Advanced Topics
Chapter
3
- Functions Of IPS System
