Nortel Communication Server 1000 Manual page 18

18 Overview
operate in parallel over the signaling channel. Various messages are
defined; each message has mandatory data elements and may include
additional optional information.
Note:
is, timeslot 17 and LAP 17 are associated with traffic channel 16), but
in the implementation the timeslot numbers are used to number the
traffic channels.
Each traffic channel, together with its LAP, represents one trunk and can
be used for a call independently of the other channels for an incoming or
outgoing call.
Each 2.048 Mbit/s link must be connected to an ISDN local public
exchange. Some channels on the link may be configured to support the
TIE Line Signaling facility, which allows a DPNSS1 connection to be
established between PBXs through the public ISDN.
Link designation
The ends of each inter-PBX link are labelled arbitrarily A and B, and the
ends of each DASS2 channel are designated X and Y. The X end has
priority if both ends attempt to use the channel at the same time.
PBX functions
A PBX that connects a DASS2 channel to or from a non-DASS2 device
is termed an end PBX. If that device is a trunk, then the PBX is termed a
gateway. A PBX connecting two DASS2 channels is a transit.
Configuration of trunks
DASS2 trunks are configured using the same route and member method
used for other trunks, thus:
•
Any number of routes may be associated with the same link.
•
A route may be associated with any number of links.
•
Each route member must be assigned to one channel.
•
Not all channels need to be associated with members. These
non-associated channels cannot, however, be used for calls.
•
Members and channels must be numbered separately.
•
Members are screened for outgoing calls using a linear search
(Sequential Line) or round robin (Cyclic Line). For DASS2 links, a
linear search should be used.
•
Each route may be configured only for incoming calls, only for outgoing
calls, or for both.
•
Each route must be configured with DASS2 channels only.
British Telecom (BT) numbers the traffic channels 1-30 (that
Nortel Communication Server 1000
DASS2 Fundamentals
NN43001-571 04.01 4 June 2010
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