Ls Trunks Selection In The Uk; Ls Trunks, Acceptable Noise Levels - Mitel 3300 ICP Hardware Technical Reference Manual

C 3
HAPTER

LS Trunks Selection in the UK

This following information is only relevant for installations in the UK:
When connecting the 3300 ICP to Local Exchange lines via LS trunks it is important that the correct
•
line type be used.
The installer or system administrator should request that the Telco (e.g. BT), or carrier, provide trunks
•
that are compatible to System X line type '0' (Subscriber lines) or line type '3' (business PBX/PABX
lines).
Both types of lines will work satisfactorily with the 3300 ICP, however line type '3' is the preferred line type
for connecting a PBX/PABX.

LS Trunks, Acceptable Noise Levels

The information in the following table is based on North American transmission specifications and is
provided for North American installations. Other regions or countries will have similar specifications which
should be referred to when installing product in regions other than North America.
For best performance, analog trunks should meet or exceed the "acceptable" values in the following table.
If an analog trunk fails to meet the "acceptable" values the issue should be addressed with the service
provider.
The values specified for Circuit Noise, Power Influence and 3 kHz Flat Circuit Noise assume a transmis-
sion level of 0 dB. For interface transmission levels other than 0 dB, the specified values should be shifted
by a value that corresponds to the difference between the transmission level at that interface and 0 dB.
Transmission Quality
Table 3.16:
Circuit
Transmissi Noise
on Quality (dBrnc)
Acceptable ‹=20
Marginal 20-23
›25
Unacceptab
le
dBrnC: Decibels above Reference Noise with C-message weighting.
dBrn3KHz: Decibels above Reference Noise with 3 KHz flat noise weighting.
The following tables provide the impedance values for each Balance Network Setting option (CO Trunk
Circuit Descriptor form) depending on the country variant of the system.
: The ASU and Universal ASU are not supported in China.
NOTE
2 kHz Flat
Circuit Power
Noise Influence
(dBrn3kHz) (dBrnC)
‹=40 ‹=80
40-60 80-90
›60 ›90
S
ERVICES
Circuit
Balance Circuit
(dB) Loss (dB)
›=60 ›=6
50-60 6-8
‹50 ‹8
P A
IN LLOCATIONS
U G
NITS AND ATEWAYS
Loop
Current
(mA)
›=23
18-23
‹18
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