Instruction manual

DEFINITY® Business Communications System and GuestWorks® Issue 6
Overview
555-231-208
Issue 1
April 2000
Networking Solutions
9-8Network interfaces and equipment
9
Tie trunks
Tie trunks carry communications between the systems in a private network.
Several types of trunks can be used, depending on the type of private network you
establish. Tie trunks use a variety of signaling types such as ear and mouth
(E&M), A-law companding, Mu-law companding, Type 1, and Type 5.
Auxiliary trunks
Auxiliary trunks connect devices in auxiliary cabinets with the system. Some of the
features that are supported with this type of trunk are recorded announcements,
telephone dictation service, malicious call trace, and loudspeaker paging.
Digital trunks
The system supports both E1 and Digital Signal Level 1 facilities. As industry
standards around the world, E1 and Digital Signal Level 1 provide the latest
alternative to analog trunking.
E1 interface
The system also supports E1 connections. T1/E1 access and conversion allows
simultaneous connection to both T1 (1.544 Mbps) and E1 (2.048 Mbps) facilities
(using separate circuit packs).
T1 interfaces
When planning your networking requirements, one of the options you should
consider is multiplexing over Digital Services 1 (DS1) facilities. As the industry
standard for interconnecting digital systems, DS1 is an economical alternative to
analog trunking arrangements. Multiplexing up to 24 digitized voice/data
communications paths onto a single T1 carrier or other high-speed digital facility
(such as fibre or microwave) can reduce your network trunking and equipment
costs.
Used to connect systems to the public network or to other systems in a private
network, Digital Signal Level 1 also delivers high-speed, end-to-end digital con-
nectivity. Voice and data calls are completed at transmission speeds of up
to 64 kbps.
The system offers several options in supporting the Digital Signal Level 1 inter-
face. The options include support for voice-grade Digital Signal Level 1 and alter-
nate voice/data. The voice-grade Digital Signal Level 1 interface is a T1 D4
channel-bank-compatible interface that does the following:
■ Uses in-band bit-robbed signaling to provide 24 voice-grade-only tie trunks
consisting of 56 kbps channels for voice and voice-grade data transmission
■ Interconnects the system with other systems with an external D4 channel
bank or with other systems (analog or digital) having the appropriate
interfaces