Nortel Networks Circuit Card 311 - Manual (Page 42)

42 Overview
Lineside T1 card has operational limitations compared to typical ground
start interface equipment relating to start of dialing, distant end disconnect
and glare potential.
Distant end disconnect restrictions If the SAL feature is not available
in the CS 1000 software, the Lineside T1 card is not capable of indicating
to the Customer Premise Equipment (CPE) when a call is terminated by
the distant end. In this case, the Lineside T1 card continues to provide
a grounded tip indication (A=0) to the CPE until it detects an open loop
indication (A=0) from the CPE, at which time it provides an open tip
indication (A=1). Therefore, without SAL software, the Lineside T1 card is
not capable of initiating the termination of a call to the CPE.
With the SAL software configured for each Lineside T1 line, the Lineside
T1 card provides an open tip indication to the CPE when it receives an
indication of supervised analog line from the system. This provides normal
ground start protocol call termination.
Glare restrictions In telephone lines or trunks, glare occurs when a call
origination attempt results in the answering of a terminating call that is being
presented by the far end simultaneously with the call origination attempt
by the near end.
The Lineside T1 detects presentation of a terminating call (outgoing to
Lineside T1 terminal equipment) by detecting ringing voltage. If application
of the ringing voltage is delayed due to traffic volume and ringing generator
capacity overload, the Lineside T1 ground start operation cannot connect
the tip side to ground to indicate the line has been seized by the system.
In ground start mode, glare conditions need to be considered if both
incoming and outgoing calls to the Customer Premise Equipment (CPE) are
going to be encountered. If the system and the CPE simultaneously attempt
to use a Lineside T1 line, the system completes the call termination. It
does not back down and allow the CPE to complete the call origination,
as in normal ground start operation.
If both incoming and outgoing calls are to be handled through the Lineside
T1 interface, separate channels should be configured in the system and
the CPE for each call direction. This eliminates the possibility of glare
conditions on call origination.
Voice frequency audio level
The digital pad for Lineside T1 card audio level is fixed for all types of
call connection (0 dB insertion loss in both directions), and differs from
the analog line. Audio level adjustments, if required, must be made in the
Lineside T1 terminal equipment.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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