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Trunk Management
DEFINITY Enterprise Communications Server Release 8.2
Overview
555-233-002
Issue 1
April 2000
T1 Interfaces
When planning your networking requirements, one of the options you should consider is
multiplexing over Digital Services 1 (DS1) facilities.
Used to connect switches to the public network or to other switches in a private network,
DS1 also delivers high-speed, end-to-end digital connectivity. Voice and data calls are
completed at transmission speeds of up to 64 kbps.
DS1 Trunk Service
Bit-oriented signaling that multiplexes 24 channels into a single 1.544-Mbps stream. DS1
can be used for voice or voice-grade data and for data-transmission protocols. E1 trunk
service is bit-oriented signaling that multiplexes 32 channels into a single 2.048-Mbps
stream. Both DS1 and E1 provide a digital interface for trunk groups.
Answer Detection
For purposes of Call-Detail Recording (CDR), it is important to know when the called
party answers a call. DEFINITY ECS provides three ways to determine whether the far
end has answered an outgoing call.
■ Answer Detection — A call-classifier board detects tones and voice-frequency
signals on the line and determines whether a call has been answered. This method
is fairly accurate.
■ Network Answer Supervision- The Central Office (CO) sends back a signal to
indicate that the far end has answered. If a call has traveled over a private network
before reaching the CO, the signal is transmitted back over the private network to
the originating system. This method is extremely accurate, but is not available in
the United States over CO, FX, or WATS trunks.
■ Answer Supervision by Time-out — You set a timer for each trunk group. If the
caller is off-hook when the timer expires, the DEFINITY ECS assumes that the call
has been answered. This is the least accurate method. Calls that are shorter than
the timer duration do not generate call records, and calls that ring for a long time
produce call records whether they are answered or not.
233002_1.book Page 84 Monday, February 21, 2000 8:28 AM