Nortel Communication Server 100 Manual page 37

Engineering guidelines 37
and the third link can be used as a spare link. The spare link is used when
one of the primary links fails. In that case, the traffic from the failed link is
automatically switched to the spare link.
The T1 carrier link used twisted-pair wire. The public network link
construction is the responsibility of the local telephone company. The only
cable routing that has to be done at the local and remote sites is from the
telephone company's telco demarcation point or Line Terminating Unit
(LTU) to the system and to the Carrier Remote IPE column or Carrier
Remote IPE cabinet.
If a private T1 network is used, the same conditions as with the public
network apply; that is, the only cable routing that has to be done at both
sites is from the CSU or telco demarcation point to the system and to the
Carrier Remote IPE column or Carrier Remote IPE cabinet, assuming that
the carrier link already exists and does not have to be constructed.
The local carrier interface and the remote carrier interface to the carrier
link are designed for in-house environment carrier protection. To protect
the carrier link in the external environment, which is susceptible to
lightning, external line protection circuits similar to trunk protection circuits
are required before the carrier link exits the building.
The carrier link line coding is B8ZS. The source of the clock for the carrier
links is the local system. The preferred framing for the T1 link is ESF (D4
is also supported).
Engineering the E1 carrier link
An E1 carrier link can be constructed using coaxial cable or twisted-pair
wire over the private or public network.
When engineering a carrier link, determine the number of links required to
support the traffic at the remote site. Local and Remote Carrier Interface
cards support from one to three E1 carrier links. These three links can be
used as primary links without a spare, or two links can be used as primary
and the third link can be used as a spare link. The spare link is used when
one of the primary links fails. In that case, the traffic from the failed link is
automatically switched to the spare link.
The E1 carrier link, in some applications, may use coaxial cable to span
the distance between the system and the Carrier Remote IPE. The public
network link construction is the responsibility of the local telephone
company. The only cable routing that has to be done at the local and
remote sites is from the telephone company's demarcation point or line
terminating unit (LTU) to the system and to the Carrier Remote IPE column
or Carrier Remote IPE Cabinet.
Nortel Communication Server 1000
Carrier Remote IPE Fundamentals
NN43021-555 04.01 4 June 2010
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