Metrodata DC3445 Manuale utente
Metrodata Ltd
Fortune House
Crabtree Office Village
Eversley Way
Egham
Surrey TW20 8RY
United Kingdom
tel: +44 (0) 1784 744700
fax:+44 (0) 1784 744730
website: www.metrodata.co.uk/support
Metrodata DC3445 User Manual
DC3445
www.metrodata.co.uk
CONTENTS
1 INTRODUCTION 1
About the DC3445 1
Safety 2
Electromagnetic Compatibility 2
Power Supply 2
FCC Declaration 2
Technical Overview 3
Signal Transmission 3
2 DESCRIPTION OF PARTS 4
Rear panel 4
Status display - rear panel 4
Power Supply 4
Unbalanced E3/DS3 Line port (BNC) 5
Alarm Extension (RJ45) 5
HSSI DTE Port 6
3 INSTALLATION & SET-UP 7
Setting-up the Bit-switches 7
E3/DS3 Enable 8
Timing 8
Line coding 8
Test Loop 8
Connecting up 9
4 ALARMS, TROUBLESHOOTING & TESTING 10
Alarms 10
Troubleshooting 11
Test Loop 12
5 DC3445 SPECIFICATIONS 13
DC3445 Product Specification 13
DC3445 Clocking Diagram 14
Glossary 15
INTRODUCTION
1
1 INTRODUCTION
1. 1 About the DC3445
The DC3445 is used to connect high performance bridges and routers to high speed E3 or
DS3 services. The DC3445 interfaces an E3 service (34.368 Mbps) or a DS3 service (44.736
Mbps) and Data Terminal equipment presenting a High Speed Serial Interface (HSSI). The
E3/DS3 selection is made by setting a bit-switch mounted on the base of the unit. DC3445’s
are used in pairs, one on either side of a WAN (Wide Area Network) link.
Figure 1. 1 DC3445 installation
LAN
LAN
INTRODUCTION
2
1. 2 Safety
The DC3445 should not be connected to cabling which would be required by BS6701 to be
equipped with over-voltage protection. The following ports are designated SELV (Safety
Extra Low Voltage) within the scope of EN41003:
HSSI port (DTE)
E3 or DS3 port (LINE or WAN)
Alarm extension RJ45 port
These ports should only be connected to SELV ports on other equipment in accordance with
EN60950 clause 2.3.
1. 3 Electromagnetic Compatibility
In order to ensure EMC compliance all signal and data cables and connectors must use a
screened connector shell with a screened cable. The cable screen must be terminated to the
screened connector shell and not connected to any pins of the connector. Failure to use the
correct connector may compromise EMC compliance.
1. 4 EN50022 Declaration
The DC3445 is a Class A product. In a domestic environment it may cause radio interference
in which case the user may be required to take adequate measures.
1. 5 FCC Declaration
This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause
harmful interference to radiocommunications. Operation of this equipment in a residential
area is likely to cause harmful interference in which case the user will be required to correct
the interference at its own expense.
1. 6 Power supply
The DC3445 is powered by a mains power supply with an input voltage range 100-250 VAC/
50-60 Hz.
An alternative -48V DC power supply unit is available.
Further details are given in Section3.
Safety notes:
Excessive voltages are present inside the unit. There are no user serviceable parts inside
the unit, and the cover should not be removed by unqualified personnel. The unit must not
be exposed to damp or condensing conditions. The DC3445 must be connected to safety
earth for correct operation.
INTRODUCTION
3
1. 7 FCC Declaration
This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause
harmful interference to radiocommunications. Operation of this equipment in a residential
area is likely to cause harmful interference in which case the user will be required to correct
the interference at its own expense.
1. 8 Technical Overview
The DC3445 is used on unframed E3/G.703, or unframed DS3/G.703 digital services.
The product conforms with Directive 1999/5/EC (RE & TTE Directive). It also conforms with
the following Common Technical Regulations: 72/23/EEC (Low Voltage Directive),
89/336/EEC (EMC Directive) and EN 60950 (Safety).
1 . 8. 1 Signal Transmission
The signal is transmitted on 75 Ohm unbalanced coax. The signal has alternate mark
inversion (AMI) characteristics in accordance with G.703. A mark is transmitted as a 0⋅5 unit
interval (UI) wide pulse of amplitude 2.37V (75 ohm). Alternate marks have opposing polarity
so that '111' is transmitted as a positive pulse, a negative one and then another positive one.
The pulses have a duration of 50% so that strings of '1s' can be identified as a series of
pulses. This is because clocking information is derived from the transmitted signal. In
addition, strings of zeros are replaced with high-density binary 3 (HDB3) code words to
ensure pulse density (and therefore clocking information) and an average DC potential of 0V.
The transmission rate is 34.368 Mbps for E3, and 44.736 Mbps for DS3 connections.
The worst case delay through the DC3445 is 2 milliseconds, and the worst case round trip
delay is 8 milliseconds.
DESCRIPTION OF PARTS
4
2 DESCRIPTION OF PARTS
2. 1 Rear panel
All connections into and out of the DC3445 are made through the rear panel. The rear panel
is shown in schematic form below.
Figure 2. 1 DC 3445 rear panel
2. 2 Status display - rear panel
There is a status LED on the right hand side of the rear panel which indicates the status of
the unit as shown in the figure below.
Figure 2. 2 Rear panel status LED
2. 3 Power Supply
The DSU is powered by a mains supply with an input voltage of 100-250VAC 50-60Hz and
with an input current of 115-45 mA. Input power consumption is approximately 4.5 watts.The
DC3445 is provided ex-factory with a 250mA internal fuse. AC Mains power is connected via
the IEC inlet on the rear of the unit.
An alternative -48VDC powered unit is available. The input voltage and current ranges are
minus 36 to minus 72 volts DC, 150-70 mA. A Buccaneer type socket is fitted to the rear
panel, and a plug is provided with the unit for the customer’s own wiring. The connections
are labelled on the rear panel of the DC3445. On some units, an additional Ground stud may
be located on the rear panel to permit a separate Ground connection to be made. The DSU
must be connected to mains safety earth for correct operation.
Figure 2. 3 -48VDC connections
Status LED Meaning
Off No mains power present
Red steady LOS
Red/Off flashing LOS and DTE Alarm
Green/Off flashing DTE Alarm
Green steady DC3445 is operating normally
Pin no Connection
1-48VDC
2 Ground
30VDC
ALARM
EXT
Status
HSSI PORT
DESCRIPTION OF PARTS
5
2. 4 Unbalanced E3/DS3 Line port (BNC)
The network is connected to the BNC connectors at the rear of the unit as shown below :
Figure 2. 4 BNC connection
Cable lengths should be restricted to those defined below:
Figure 2. 5 Cable lengths
Note: The total maximum attenuation of each of the cables attached to the network port must
not exceed 6dB when measured at 17.184 MHz (E3) or 22.368 MHz (DS3). The frequency/
attenuation characteristic of the cables attached to the network port shall follow a root
frequency law.
2. 5 Alarm Extension (RJ45)
The alarm extension is an RJ45 female socket mounted on the rear panel of the unit. It allows
the connection of major and minor alarm relay contacts to a remote indicator such as a bell
or a lamp. The alarm relay port is regarded as a SELV port within the scope of EN41003.
Mains power failure is registered via Normally Closed contacts as a major alarm.
Figure 2. 6 RJ45 alarm extension layout
Pin Function
Tip Signal
Ring Shield
Cable E3 Max Length
(metres)
DS3 Max Length
(metres)
UR202 180 155
RG59U 150 130
BT2002 160 140
BT2003 165 145
Pin Function
1Major Normally Closed
2Major Normally Open
3Major common
4Not connected
5Minor Normally Open
6Minor Normally Closed
7Minor common
8Ground
DESCRIPTION OF PARTS
6
2. 6 HSSI DTE Port
The HSSI EIA613 DTE port is used to connect to the router. It consists of a female miniature
50-pin AMP connector, whose pins are described below.
AMP connector, part number 749111-4 or should be used for connections to this port.
Note: The HSSI port is regarded as a SELV port within the scope of EN 41003.
Figure 2. 7 HSSI port connector layout
+VE Pin
No
-VE Pin
No
Function CCT No.
126 SG 102
227 RT 115
328 CA 107
429 RD 104
530 LC
631 ST 114
732 SG 102
833 TA 108.2
934 TT 113
10 35 LA 141
11 36 SD 103
12 37 LB 140
13 38 SG 102
14-18 39-43 Reserved
19 44 SG 102
20-23 45-48 Reserved
24 49 TM
25 50 SG 102
INSTALLATION & SET-UP
7
3 INSTALLATION & SET-UP
3. 1 Setting-up the Bit-switches
It is recommended that the bit-switches on the base of the unit are set-up before making any
connections to the unit. There is an explanatory label on the unit’s base which defines the
bit-switch set-up options and alarms.
Figure 3. 1 DC3445 Base Panel label
Figure 3. 2 Bit-switch definitions
Parameter Label Unit Options
E3/DS3 E3/DS3 Enable Up Down DS3 or E3
Timing Clock select Position Internal or Loop
Test Test Loop On Off Run Test Loop or No Test
TEST
LOOP
OFF ON
Serial No:
DC3445 E3/DS3-HSSI (AC)
For product manual
and other information:-
www.metrodata.co.uk
Metrodata Ltd
TW20 8RY UK
Tel +44 (0) 1784 744700
Fax +44 (0) 1784 744730
17-08-199A
SPARE
CLOCK SELECT
INTERNAL
LOOP
E3/DS3 ENABLE
DS3 MODE
E3 MODE
Part No 80-05-234
INSTALLATION & SET-UP
8
3 . 1. 1 E3/DS3 Enable
This switch is used to select the line (WAN) to be connected to the DC3445. Options are E3
or DS3.
3 . 1. 2 Timing
The E3/DS3 Line TX clock is derived from the DTE using CCT 113 (TT: terminal timing). The
HSSI specification requires this signal to be a non-gated version of CCT 114 (ST: send
timing).
The E3/DS3 Line Rx clock is always used to generate the CCT 115 timing (RT: receive
timing).
With INTERNAL timing selected, Send Timing (ST) is derived from the DC3445's own
internal oscillator. With LOOP timing selected, ST is derived from the E3/DS3 LINE Receive
clock.
The recommended timing mode for the DC3445 pair at either side of the WAN is Internal at
one end of the link and Loop at the other end.
3 . 1. 3 Line coding
This setting is automatically selected when the Line is selected (no bit-switch) and cannot be
altered. It is HDB3 (High-Density Binary 3) for E3 and B3ZS (Binary 3 Zeros Suppression)
for DS3.
3 . 1. 4 Test Loop
This switch is used to initiate loop testing. It is fully described in the next section.
Indice
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