PRACTICE 553-2201-182
3. DTI LOSS TABLES
+I
3.01 Tables 3-A through 3-D provide the insertion loss specifications of
the SL-1 Business Communications System when it is equipped with a
QPC472 Digital Trunk Interface (DTI).
3.02 The insertion loss for connections between analog ports of the
SL-1 and the
DTl
or beteween DTI ports is connection-specific in
order to be compatible with end-to-end network connection loss
requirements. SL-1’ connection loss specifications are in agreement with
U.S. and Canadian standards which are formulated to provide
satisfactory transmission on connections between switches in a *private
network and between a private network and the public network.
(EIA
Communications Interim Standard. CIS-4 (U.S.); Department of
Communications Standard CS-03 (Canada).) This formulation is based
on the use
Qf
a fixed loss plan for digital portions of these connections.
As a result. certain connections through the SL-1 are asymmetrical: this
asymmetry is resolved at the far end of the connection.
3.03 Tie trunk connections to a satellite PBX require different loss
treatment than non-satellite
Lie
trunks. The insertion loss for satellite
tie trunk connections is given in Tables 3-C and 3-D. Loss values
associated with tie trunks in Tables 3-A and 3-B should not be applied
to satellite PBX tie trunk connections.
. .
Note: In
this
NTP. “satellite” denotes a PBX which homes on a
main PBX and does not have a
directorv
number for
incoming
calls: satellite tie trunks are trunks connecting such a PBX to
the
main PBX. There is no explicit or implied reference to facilities
usuing satellite (i.e.. space vehicle) circuits.
3.04 In these tables. the notation “1000 Hz Insertion Loss” refers to a
sinusoidal signal having a frequency between 1000 and 1020
Hzrthe
value of 1004 Hz has been standardized in the telephone industry in
order to avoid frequency beating of an exact 1000 Hz signal in the
presence of PCM carrier systems.
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