Nortel 1000 Features And Services Fundamentals page 434

434 China - Supervised Analog Lines
has disconnected. If the terminal device disconnects first, the system sends
the Deactivate Battery Reversal Scan Signal Distribution (SSD) message
to the firmware after receiving the on-hook status to revert the polarity to
its idle state.
Two types of battery reversal are supported. Battery Reversal for Absolute
Answer Only provides an answer supervision signal to the terminal device
only when the system detects an absolute answer. Battery Reversal for
Absolute and Assumed Answer provides an answer supervision signal to
the terminal device even when an assumed answer is detected and the far
end is not capable of indicating definite answer (for example, an outgoing
call on an unsupervised loop start trunk).
Hook Flash Disconnect Supervision
Hook flash disconnect supervision is used for incoming calls terminating at
the terminal device. The disconnect signal is indicated by the removal of
the ground connection to the tip lead for a specific period of time, which
is provided by firmware ranging from a minimum of 10 milliseconds to a
maximum of 2.55 seconds. The analog port is held busy for incoming calls
while hook flash is in progress.
Operating parameters
This feature applies to Intelligent Peripheral Equipment that support the
Supervised Analog Line feature only.
Disconnect supervision is not provided to the terminal device if the system
does not receive any indication of the far end releasing.
If the system does not receive any answer indication, and answer
supervision is not extended to the terminal device following an assumed
answer condition, disconnect supervision cannot be extended when the
far end disconnects.
If the Battery Reversal Supervision feature is configured for an analog
line on an analog card that does not support battery reversal, the battery
reversal SSD messages from the system software are ignored by the analog
card firmware. In this case, no battery reversal signal is extended to the
terminal device.
If the Hook Flash Disconnect Supervision feature is configured for an
analog line on an analog card that does not support hook flash, the hook
flash SSD messages from the system software are ignored by the analog
line card firmware. In this case, no hook flash signal is extended to the
terminal device.
Copyright © 1994–2008, Nortel Networks
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Nortel Communication Server 1000
Features and Services Fundamentals — Book 2 of 6 (C)
NN43001-106 02.04 Standard
Release 5.5 9 May 2008