IRT DDA-4280 User manual

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IRT Eurocard
Type DDA-4280
2.048 Mbps (E1) G.703
Data Distribution Amplifier
Designed and manufactured in Australia
IRT can be found on the Internet at:
http://www.irtelectronics.com
I R T Electronics Pty Ltd A.B.N. 35 000 832 575
26 Hotham Parade, ARTARMON N.S.W. 2064 AUSTRALIA
National: Phone: [phone] Fax:[phone]
International: [phone] [phone]
Email: [email protected]
Web: www.irtelectronics.com

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IRT Eurocard
Type DDA-4280
2.048 Mbps (E1) G.703
Data Distribution Amplifier
Instruction Book
Table of Contents
Section Page
Operational Safety 2
General Description 3
Functional Diagrams 4
Technical Specifications 5
ZDA-4300RH Technical Specifications 6
Electrical characteristic of ITU-T G.703 2.048 Mb/s (E1) signal 6
Coding characteristic of ITU-T G.703 2.048 Mb/s (E1) signal 7
G.703 data signal format 7
Configuration 8
Installation 9
SMU-4000 Installation 11
Figure 1: SMU-4000 module 11
Front and rear layouts 12
Operation 13
SNMP –What Is It? 14
DDA-4280 SNMP Functions 16
Maintenance & Storage 17
Warranty & Service 17
Equipment return 17
This instruction book applies to units later than S/N 0901001.
Operational Safety:
WARNING
Operation of electronic equipment involves the use of voltages and currents that may
be dangerous to human life. Note that under certain conditions dangerous potentials
may exist in some circuits when power controls are in the OFF position.
Maintenance personnel should observe all safety regulations.
Do not make any adjustments inside equipment with power ON unless proper
precautions are observed. All internal adjustments should only be made by suitably
qualified personnel. All operational adjustments are available externally without the
need for removing covers or use of extender cards.

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IRT Eurocard
Type DDA-4280
2.048 Mbps (E1) G.703
Data Distribution Amplifier
General Description
The DDA-4280 data distribution amplifier is intended for use with E1 data signals conforming to the
ITU Rec. G.703. The DDA-4280 is primarily intended for use in pairs with a double width rear assembly for
automatic path protection applications, although it is supplied as standard with its own rear assembly for stand-alone
applications.
Four outputs are provided at the rear of the module with an additional output for monitoring purposes on the front
panel. One output (O/P 1) is controlled by relays to provide a bypass signal from the input in the event of a power
failure.
Indicators are provided on the front panel for:Data loss
AIS detect
Module in service
Module in standby
Changeover inhibit and changeover request switches are provided on the front panel for use where modules are
linked in pairs for redundancy. For this configuration the double width rear assembly is needed to link the logic
sections of two modules.
When used as a distribution amplifier the DDA may be housed in any of IRT’s standard Eurocard frames. When
used in pairs for handshake operation only 3 RU chassis types may be used so that the double width rear assembly
may be used.
The DDA-4280 is also equipped with Simple Network Management Protocol (SNMP) monitoring so that status and
alarms can be remotely monitored and controlled via an Ethernet connection. This function is only available when
the unit is housed in an IRT 4000 series frame fitted with an SNMP agent module.
Standard features:
•Data regeneration with Jitter Attenuator
•Front panel monitoring facility.
•Protection switching facility.
•External alarms and bypass.
•Redundant pair operation capability.
•Simple Network Management Protocol (SNMP) monitoring.

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Functional Diagrams
J 3
ZDA-4300RH Handshake Diagram
J 2
J 4
INPUT
1J1
RELAY
RL1.1
RELAY
RL1.2
OUTPUTS
DDA-4280
SIGNAL
PROCESSING
RELAY
RL5-2
INPUT
2J1
RELAY
RL1.1
RELAY
RL1.2
RELAY
RL5-2
RL2-1
RL2-1
RL3
RL3
Output Driver
FPGA
E1Generator,
Change over logic,
AIS Detector
INPUT
(SK
5
)
RL1-2
OUTPUTS
(SK4)
Data
Reg. with
Jitter Att
MON
(SK
2
)
Block diagram DDA-4280 -Signal path
(SK9)
(SK8)
Output Driver
Output Driver
Output Driver Output Driver
(SK13)
RL1-1
O/P 1
O/P 4
O/P 3
O/P 2
GND
(
SK6
-
3
)
SNMP
Control
RL5-2
RL2-2
RL2-1
RL3-1
General Alarm
(
SK6
-
2
)
Power Fail Alarm
(
SK6
-
1
)
DDA-4280
SIGNAL
PROCESSING

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Technical Specifications
IRT Eurocard module
Type DDA-4280
In accord with ITU-T Rec. G.703 –see Electrical characteristics of G.703 signals.
Input:
Type Transformer coupled.
Impedance 75 Ωterminated.
Outputs:
Number 1 switched, 3 non-switched, regenerated, reclocked shaped outputs located
on rear connection assembly and 1 located on front panel.
Impedance 75 Ωsource terminated.
Electrical Characteristics:
Cable Type Coaxial
Other See G.703 Specification for 2.048Mb/s data rate
Controls & alarms:
Input:
External changeover request A ground applied to this input will emulate the operation of the front
panel switch “Change Request”.
Outputs:
Power failure Contact to open circuit if power has failed.
General alarm Contact to open circuit if
Data Loss is detected OR AIS is detected
Connectors: Data: BNC
Alarm: Krone LSA plus
Indicators: Data loss.
AIS detect.
Module in service.
Module in standby.
Power requirements 28 Vac CT (14-0-14) or ±16 Vdc.
Power consumption < 4 VA
Temperature range 0 -50° C ambient
Mechanical Suitable for mounting in IRT 19" rack chassis types with input output and
power connections on the rear panel.
Finish: Front panel: Grey background, black lettering & red IRT logo.
Rear assembly: Detachable silk-screened PCB with direct mount connectors to Eurocard
and external signals.
Dimensions 6 HP x 3 U x 220 mm IRT Eurocard
Standard accessories Rear connector assembly.
Optional accessories ZDA-4300RH Double width rear assembly for handshake connection of
two DDA-4280's (number of outputs drops to 3).
Due to our policy of continuing development, these specifications are subject to change without notice.

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ZDA-4300RH Technical Specifications
Controls & alarms:
Outputs:
Bypass Contact to open circuit if power has failed.
General Alarm Contact to open circuit if:-
a. Data Loss is detected OR
b. AIS is detected AND the AIS disable switch (SW3-4) is not set.
In Service (Main) Path Indication Transistor switch to ground if card is active.
Connectors: Data: BNC.
Alarm: Krone LSA plus.
In Service (Main) Path: Krone LSA plus.
Changeover logic:
A changeover to the companion module will occur under any of the following conditions:
Loss of input signal
AIS detection alarm (provided AIS is not disabled by switch SW3-4)
Loss of power
In all of the above cases switching will only occur if:
companion module is able to provide an output free of the same defects and
changeover inhibit switch is not activated on either module.
Priority logic:
The priority switching in normal mode follows non reverting logic which dictates:
In the event of failure of main then standby DDA will assume control and become Main causing the failed
path DDA to become Standby.
This implies that when the failed path is restored that it will remain as Standby and not become Main unless either a
failure of Main occurs or a manual changeover is requested.
Power on reset.
When power is applied to the pair, the power on reset signal will set the module which was last enabled as Main as
Main and the other module will be forced to act as Standby.
When power is applied to a pair for the first time it may be necessary to force the desired module to become Main by
pressing the Change Request button on the front panel of the desired module. The Main module will be indicated by
the In Service LED being lit on the front panel.
Due to our policy of continuing development, these specifications are subject to change without notice.
Electrical characteristics ITU-T G.703 2.048 Mb/s (E1) signal:
Cable Type Coaxial
Impedance 75 Ω
Signal level 2.37 V
Nominal pulse width 244 ns
Code conversion HDB3
Pulse shape Fig. 15 of ITU-T G.703 Specification (11/2001).
Jitter at input port Section 7 of ITU-T G.823 Specification (03/2000).
Jitter at output port Section 5 of ITU-T G.823 Specification (03/2000).
Return loss at input ports:
51 kHz to 102 kHz 6 dB
102 kHz to 3072 kHz 8 dB

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Coding characteristic of ITU-T G.703 2.048 Mb/s (E1) signal:
The HDB3 (High Density Bi-polar of order 3) code as defined in G.703 for 2.048 Mb/s (and 34.368 Mb/s)is as
follows:
Binary 1 bits are represented by alternate positive and negative pulses and binary 0 bits by spaces. Exceptions
are made when strings of successive 0 bits occur in the binary signal.
Each block of 4 successive zeros is replaced by 000V or B00V where B is an inserted pulse of the correct
polarity and V is an inserted pulse violating the polarity rule. The choice of 000V or B00V is made so that the
number of B pulses between consecutive V pulses is odd so that successive V pulses are of alternate polarity
and so no DC component is introduced.
G.703 data signal format.
The following waveforms are intended to give some idea of the type of signal at various points in the DDA when in
operation. They are not intended as accurate portrayals of either voltage levels or timing.
It can be seen that the original signal has both positive and negative going pulses. This format is used so that the
signal does not rely on DC levels. To preserve the AC nature of the signal a coding system is used to ensure that a
succession of either ‘1’s or ‘0’s in the original data does not produce a DC output. The coding system varies
according to the type of G.703 signal (See specifications for each module and Coding characteristics above.)
It can be seen that the cable effected signal bears little resemblance to the original signal and due to the high
frequency attenuation looks more like a noisy analogue signal than a digital signal. The input equaliser circuit in the
DDA enhances the high frequency response and detects the rate of change of the signal to produce a squared up
signal with fast rise and fall times suitable for processing and re-clocking.
Original signal
Cable effected signal
Equalised signal

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Configuration
The only user settings on the DDA-4280 is on the DIP switch SW3 as shown below:
SW4-1Not used.
SW4-2Not used.
SW4-3Not used.
SW4-4 OFF Disable switching on AIS†input (when used in handshaking mode).
ON Enable switching on AIS†input (when used in handshaking mode).
SW4-5Not used.
SW4-6Not used.
SW4-7Not used.
SW4-8Not used.
NOTE: †AIS stands for Alarm Indication Signal.
ZDA-4300RH Link Settings:
When the ZDA-4300RH is used with a DDA-4280, Direct links LK1, LK3 and LK5 should be installed (default
position).
1
ON
2 3 4 5 6 7 8
DIP
SW3

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Installation
Pre-installation:
Handling:
This equipment may contain or be connected to static sensitive devices and proper static free handling precautions
should be observed.
Where individual circuit cards are stored, they should be placed in antistatic bags. Proper antistatic procedures
should be followed when inserting or removing cards from these bags.
Power:
AC mains supply: Ensure that operating voltage of unit and local supply voltage match and that correct rating fuse
is installed for local supply.
DC supply: Ensure that the correct polarity is observed and that DC supply voltage is maintained within the
operating range specified.
Earthing:
The earth path is dependent on the type of frame selected. In every case particular care should be taken to ensure that
the frame is connected to earth for safety reasons. See frame manual for details.
Signal earth: For safety reasons a connection is made between signal earth and chassis earth. No attempt should be
made to break this connection.
Installation in frame or chassis:
See details in separate manual for selected frame type.
G.703 data connections –stand alone operation:
For use with supplied standard rear assembly.
Connect the input and as many output connections as required. Only good quality 75 Ohm connectors and cable
should be used. The use of 50 Ohm BNC connectors may cause serious reflection problems with G.703 signals,
causing data errors.
In general cable runs should be kept as short as possible and should not exceed 200 metres for reliable error free
operation.
Stand-alone alarm connections:
A Krone type connector is provided on the rear panel of the module providing the following:
Pin 1Connection to open circuit indicates a loss of power alarm.
2Connection to open circuit indicates a general signal alarm.
3Not used.
4Ground.

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G.703 data connections -handshake operation:
The ZDA-4300RH is a double width rear assembly that takes the place of two standard rear assemblies that would
normally be fitted side by side. The ZDA-4300RH supplies the necessary controls between the two main cards.
Connect the two separate inputs and as many output connections as required. J2 corresponds to Output 1, J3
corresponds to Output 2, and J4 corresponds to Output 3. Only 3 of the 4 outputs are switched. The 4th output does
not pass through. Only good quality 75 Ohm connectors and cable should be used. The use of 50 Ohm BNC
connectors may cause serious reflection problems with G.703 signals, causing data errors.
In general cable runs should be kept as short as possible and should not exceed 200 metres for reliable error free
operation.
Handshake alarm connections:
Two Krone type connectors, 1SK2 and 2SK2, corresponding to each of the cards are provided on the rear panel of
the module providing the following:
Pin 1Connection to ground indicates module is in bypass mode (loss of power).
2Connection to ground indicates a general signal alarm.
3External changeover request –connection to ground will make this module Main in
handshake mode.
4Ground.
A third Krone type connector (SK3) provides remote status of which unit is In Service (Main).
Pin 1Connection to ground indicates that module 1 is the In Service (Main) module.
2Connection to ground indicates that module 2 is the In Service (Main) module.
3Ground.