Digital 2 Mbit/s Branching Equipment

DY N A N E T
DB2
Digital 2 Mbit/s
Branching Equipment
DY N A N E T
City road
DM2
2M
DB2
L road
T road
Side road
DB2 Digital
Branching
in Networks
of Small
Capacity
2M
DM2
Technical Highlights
• Equipment, small in size,
capable of dynamic channel
branching from 2 Mbit/s
capacity
• Speech and/or data channel
drop/insert in the same
equipment with a large
variety of direct interface
units
• Protection and change-over
configurations available for
2 Mbit/s signals
• Individual channel protection
by using, for example, loop
protection
• Local and remote management
Digital Branching Equipment
The DB2 is a member of the Nokia
DYNANET family of access network products. The DB2 performs
the functions of branching equipment that can be controlled dynamically, using the DYNACARD
channel unit selection.
Applications
The DB2 equipment family offers
a wide range of different branching and drop/insert functions.
Typically, the DB2 is used in
private chain, tree or ring-shaped
networks. In these applications a
VF
or
data
small number of channels are used
at intermediate stations, where different channel types are often
needed.
The 2 Mbit/s or individual
channels must be protected when
availability is a strong requirement. In applications where dynamic network structure is the optimum solution, the DB2 is the key
component.
In public networks, dynamic
branching can be used to establish
semi-permanent or leased speech
and data lines. The DB2 is also
well-suited for data network applications, and for arranging line signal and individual channel protection. Channels from small exchanges, concentrators and remote subscriber stages
can be
collected to one 2 Mbit/s stream to
save radio frequencies, line equipment, and exchange interface
lines.
Digital Branching Principles
The DB2 branching equipment
forms a 2 Mbit/s bi-directional
branch to the main line signal. The
branch and the main line signal
have the same speed
and
frame structure. Individual chan-
VF
or
data
nels are connected through or
branched and the operation
is
completely digital. Thanks
to
the digital cross-connect matrix,
very
flexible
time-slot
rearrangements are possible. The
channel-associated signalling is
branched together with the corresponding channels.
Dropping and inserting is
achieved by plugging in VF or data
interface units to the DB2 equipment. The DYNACARD interface
units have access to all time-slots
of the signals passing through.
Dynamic Branching
Dynamic branching makes it possible to change branching configurations
during
normal
operations. This unique feature
makes it possible to fully and
flexibly use the transmission network capacity.
The various branching alternatives are stored in each DB2 in
the network. The network reconfiguration can be done manually
through the service interface or
it can be triggered automatically,
based on e.g. alarms or the time
of day. Changes in branching
DY N A N ET
configurations do not disturb
traffic on those channels that
remain unchanged.
Various Functional
Alternatives
The DB2 branching equipment
consists of two plug-in units for
branching and a wide range of VF
and data interface units for dropping and inserting individual
channels. Programming and combining the units in various ways offers an almost unlimited number
of different functional alternatives.
The four main DB2 configurations are:
•
•
DB2B, basic branching equip ment
•
DB2T, terminal (change-over)
equipment
•
DB2B-LP loop-protected branching equipment
DB2P, protected branching equipment
The protected branching
equipment, DB2P, has duplicated
interfaces for the line signals from
both directions. The built-in logic
automatically selects the better
2Mbit/s input signals to be
branched. It is therefore possible to
use the DB2P when 2Mbit/s signals
need to be protected by using two
alternative paths to the branching
point. Likewise, the DB2T can be
used as a protective hitless switch
at the end of a protected branch-
ing chain. The DB2T selects the
faultless signal in the receive direction and duplicates the signal
in the transmit direction. In ringshaped networks, the DB2B-LP
protects the individual channels
(nx32/64k) and the synchronisation.
Flexible Installation
The DYNANET installation
concept offers several flexible
installation options in the
form of wall-mounted cases,
Nokia Office Boxes, equipment cabinets, slimracks, and
19" racks. This allows you to
place units freely, including
units of Nokia transmission
equipment, in any vacant unit
space, thus increasing the configuration flexibility.
The DB2, the DM2 multiplex
equipment and the DN2 crossconnect equipment all use the
same DYNACARD channel units,
described in separate brochures.
Common Channels
The DB2 supports both VF and
digital common channels. The VFtype common channel is based on
the summing of PCM-coded signals, typically used for:
•
•
polling data connections
•
service telephone systems
base station systems for mobile
phones
The digital common channel
is based on bit-by-bit summing,
used in digital multipoint data
connections, where DYNACARD
data interface units are used, for
example.
Integrated Maintenance and
Versatile Programming
Channel Units
DYNACARD channel units can be
connected to all DB2 configurations. The VF and data interface
units are connected directly to the
internal 2 Mbit/s bus of the equipment. Each unit and channel can
be programmed for any time-slot.
The DB2, like all Nokia transmission equipment, has an intelligent
service interface for maintenance
operations and configuring equipment. Locally, the service interface
is accessed either with the handheld Nokia Service Terminal or
with a PC which is equipped with
the Macro Service Terminal Emulator (MSTE) or the DB2 Manager
program.
The DB2 service interface
offers:
•
programming of branching configurations
•
programming of operational mode
and settings
•
•
detailed alarm monitoring
•
•
signal quality measurements
test point and alarm output programming
supervision and control of channel units
Centralised network management is offered by the Nokia NMS
network management system.
Technical Data
DB2
Main Characteristics
ITU-T Recommendations
Bit rate
Bits per time-slot
Time-slots per frame
Time-slots for VF and Data
Frames per multiframe
Multiplexing
G.703, G.704, G.706, G.732,G.823, G.821
2048 kbit/s
8
32
30 (31)
16
Synchronous 32 kbit/s time-slot interchanging
Branching
Branched time-slots
VF (PCM) omnibus channels
Digital omnibus channels
Bit rate of each branched channel
Control of branching
0-30 (31) time-slots
0-30 (31) time-slots
0-30 (31) time-slots
32...1920 kbit/s (n x 32 kbit/s)
via the service interface
Electrical Interfaces
2 Mbit/s
ITU-T Recommendations
Bit rate
Code
Pulse shape
Peak voltage/impedance
Peak voltage tolerance
Input signal attenuation
G.703, G.823
2048 kbit/s ± 50 ppm
HDB3
rectangular
3V/120 ohm
2.37V/75 ohm
10%
0 to 6 dB/1 MHz
VF and data
Interface units of the DYNANET family are detailed in separate leaflets
Number of VF and Data units
Limited by cartridge space only
Power Feeding
Central battery voltage
Power consumption without
channel units
Mechanical Dimensions
20...72 VDC
DB 2B DB 2P DB 2T DB 2B-LP
5W
10 W 5 W
5W
20T cartridge (4 plug-in units)
40T cartridge (8 plug-in units)
19" subrack (16 plug-in-units)
Height
306 mm
306 mm
378 mm
Temperature
Humidity
Operation
Transport and storage
-10° to +50°C -40° to +70°C
95% at 30°C up to 98%
Environmental Specification
Electromagnetic Requirements
75-9600 bit/s, V.11 ITU-T
600-2400 bit/s, V.11 ITU-T
Width
112 mm
232 mm
480 mm
Depth
219 mm (EMC-mechanics)
219 mm (EMC-mechanics)
219 mm (EMC-mechanics)
Complies to the following requirement: prETS 300386-1 table 5
All Nokia products are subject to continuous research and development; we therefore reserve the right to alter technical specifications without prior
notice.
Nokia Telecommunications P.O. Box 370, FIN-00045 NOKIA GROUP, Finland. Phone: +358-9-51121, fax: +358-9-5112 7502
NTC code: 0029_EN_0597_3.0 Libris
Other interfaces
Service interface
Auxiliary data channel