Mechanical Design

BugFix

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EWSDMechanical Design of EWSD network nodes

General informationThe hardware used for EWSD is characterized by itscompact, modular design. The packaging system af-fords a great degree of flexibility, which allows optimumadaptation to every system architecture. The use ofconnector and interchange systems facilitate fast in-stallation times. Innovative ongoing hardware develop-ment contributes to ever smaller space requirements.

The EWSD system complies with the relevant interna-tional standards (EN60950 / IEC60950) regarding per-sonal safety, protection of materials and equipment,electromagnetic compatibility (EN55022), etc. Compli-ance with the standards is certified by the CE label onall racks.

The relevant standards for transport, storage and oper-ation (temperature, humidity, air pressure, condensa-tion, shocks and vibrations) are also adhered to.

Special system designs compliant with Bellcore TR-NWT-000063 (NEBS), Earthquake Zone 4, are sup-plied for earthquake-endangered areas.

The EWSD mechanical consists of the following maincomponents:– Modules– Module shelves– Fuse bars– Fans for rack types ’A’ and ’B’– Racks– Cabling– Distributors– Power supply and distribution– Installation recommendations– Container network nodes– Shelters

ModulesModules are the smallest units of equipment designand also have a standard format. The front of eachmodule contains a faceplate which may include displayelements, switches and front plugs.

The spring contact strips on the rear edge of the mod-ules are the counterpart to the blade contact strips inthe shelves. Plug connections are made in the SIPACor SIVAPAC connector system.

The printed circuit boards for the modules have a mul-tilayer design. They are mainly equipped as SMD (sur-face-mounted device) units.

Due to the use of electrostatically sensitive devices,electrostatic discharge (ESD) frames are even provid-ed in the module structure. All modules have a label in-dicating ESD.

The precautionary measures for handling modulesmust always be observed. These measures are de-scribed in detail in Safety Instructions for Personneland Products (EN 60950 / IEC 60950).

The modules are automatically locked into position oninsertion into the shelf. A tool is available for unlockingand withdrawing modules. The same tool is also usedfor insertion of the modules.

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Module shelvesThe module shelves constitute physical and wiringunits. A shelf consists for the most part of support bars,side parts and guide rails for modules in addition to amultilayer wiring board. Shelves can be fitted withpunched base and top plates and a contact-makingfront cover in order to provide complete electromagnet-ic screening. Electrical connections are established be-tween the mounting locations in the module shelf andfor the power supply over the wiring board. Blade con-tact strips pressed into the wiring board constitute theinterface to the modules. If necessary, the pins on theblade contact strips are selected with lengths that arelong enough to allow cable connectors to be plugged inat the rear. Suitable centering strips or cages ensurecorrect precentered positioning and locking of the cableconnectors.

Modules can be mounted with different spacings fromeach other – so-called module pitches (15 + n x 5 mm).A slot number is assigned to each slot. The usablemounting width is 645 mm. Cables to and from the shelfare routed at the rear over the connector panel of thewiring board. The operating voltages from the fuse barare connected by means of flat connectors or cableconnectors to the wiring board. Shelves can beequipped with modules using the SIVAPAC or SIPACsystem. The same applies to the transfer system – i.e.,SIVAPAC and SIPAC connector cables can be con-nected. Both methods can also be combined.

Benefits

for packaging system:– Consistent modularity: standardized,

connectable basic units (known as modules)can be combined in connection with racksto form network nodes for differentconfigurations.

– Leading-edge, solder-free connectionmethods such as press-fitting in multilayerversions.

– Simple, rational assembly by arrangement inrows of fully equipped, tested racks andprepared connector cables.

– Cables according to international standards(IEEE 383 and IEC 950), connected to therack backside by SIPAC (standard, coaxialand optical).

– Full protective rack covering with doors onthe front and rear sides allowing unrestrictedaccess to the interior.

– Shielding (double):Subrack completely screened againstelectromagnetic effects with front panel andbackplane with a shielding layer includingthe transfer system at the rear side.Rack additionally screenable by lowresistance contacts between all mechanicalparts and the housing of the rack.

– Thermal:The heat management of the racks isperformed by free convection for heatdissipation up to 1.29 kW and a forcedcooling system with filtered air blown seriallyby a fan box at the bottom of the rack, option-ally enforced by additional blower units,allowing heat dissipation of up to 3.15 kWper rack.

– Easy to service due to simple replacement ofthe modules and reliable plug connections

Benefits

for connector and transfer system:– Large number of pins possible– Consistent 2.5-mm grid system without

jumps– Five-row design with full use of the minimum

module pitch (25 mm)– Individual contact equipment– Integrated special contacts– Multiple pre-mating contact levels– Excellent connection security– Double-sided connection for modules and

interchange systems– Optimum cross-talk and transmission

characteristics– Coding provided

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Unscreened module shelves

Unscreened module shelves are available as 2-rowmodels – i.e., for equipping with one row of modules,and as 4-row models for two modules rows on top ofeach other. The mechanical design consists of themost part of horizontal channel sections which, in com-bination with the two side walls, form a stable frame.The module guide rails are snapped into position in thechannel sections. Additional support plates are used formechanical reinforcement of the shelves. The wiringboard is screwed into place at the rear. The front sur-face of a shelf is made up of the module handle strips.

Screened module shelves

Like a Faraday cage, a screened shelf is an electricallyconducting housing closed on all sides, with a front cov-er that can be locked in place (swinging or removable).All basic dimensions are identical to those of the un-screened model. Consequently, unscreened shelvescan be replaced by screened shelves without any diffi-culty. The housing with the screened design is madefully of Cr steel. The outer layers of the wiring board aredesigned as screening levels.

Fuse barsFuse bars accommodate the power feeding for a rack.Power is fed via feedthrough filters to the fuse elements(safety fuses or protective switches). The power is dis-tributed from the fuse elements to the individual loadcircuits in the rack.

Smoothing capacitors can be assigned to the individualpower feeders if necessary.

A fuse bar requires three rack divisions (90 mm) for in-stallation and is always mounted as the first mountingunit (MUT1) in a rack.

Fuse bars with safety fuses

Fuse bars have screw-in fuses for protecting the differ-ent electrical load circuits in a rack. A fuse bar can haveno more than 33 safety fuses.

Fuse bars with protective switches

This type of fuse bar is known as a breaker panel.

A breaker panel is equipped with pluggable protectiveswitches for protecting the different load circuits in arack. A breaker panel can have up to 28 protectiveswitches. Unlike a fuse bar with safety fuses, the acti-vation of a protective switch can be indicated and usedfor triggering an alarm.

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Fans for rack types ’A’ and ’B’Two types of fans can be used in racks with high levelsof heat loss that cannot be dissipated by free convec-tion. They are as follows:– Fan tray with optional filter module– Fan box

Fan trays

A fan tray for rack type ’A’ needs two rack divisions(60 mm); a fan tray for rack type ’B’ needs three rack di-visions (90 mm) and both have 10 fans with electroni-cally commutating d.c. motors. The function of eachmotor is monitored. A green LED on the front of the fantray indicates that all fan motors are functioning. If oneor more motors fail, an alarm is triggered and the LEDgoes out.

Each motor has a temperature sensor for controllingthe rotational speed of the relevant motor according tothe ambient temperature. A reduction in the number ofrevolutions of a fan motor at temperatures in the permit-ted range of 20 ˚C ... 30 ˚C considerably lessens themotor noise.

Filter modules

A filter module contains an air filter and can be retro-fit-ted directly beneath the fan tray at bottom of the rack asrequired: it is only to be used if no fan box is installed inthe rack (an air filter is included in the fan box).

The module needs one rack division for mounting(30 mm). The air filter can be replaced when necessarywithout any tools. The module must be mounted direct-ly beneath the fan tray in order to prevent any air by-pass (of unfiltered air) occurring.

Fan boxes

A fan box for rack type ’A’ needs eight divisions(240 mm) and has 6 fans with electronically commutat-ing d.c. motors. A fan box for rack type ’B’ needs tenrack divisions (300 mm) and has 8 fans with electroni-cally commutating d.c. motors. The function of eachmotor is monitored. A green LED on the front of the fanbox indicates that all fan motors are functioning. If oneor more motors fail, an alarm is triggered and the LEDgoes out.

Each motor has a temperature sensor for controllingthe rotational speed of the relevant motor according tothe ambient temperature. A reduction in the number ofrevolutions of a fan motor at temperatures in the permit-ted range of 20 ˚C ... 30 ˚C considerably lessens themotor noise.

An air filter is included; it is positioned on the undersideof the fan box and can be replaced at any time withoutany tools. The fan box produces minor excess pressurein the rack to prevent unfiltered air entering the cabinet(air bypass). Fan boxes are mounted on the bottom ofa rack.

RacksRacks accommodate the various mounting units. Theside bars of a rack have holes drilled at regular intervalsof 30 mm to allow flexible equipping of module shelves.

The upper and lower sections each constitute a closedframe. The rear-side struts are arranged in such a waythat cables can be laid without feed-throughs. The ba-sic frame has four feet that can be adjusted in height.

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The numbering of the module shelves in a rack, knownas mounting units (MUT), always begins at the top withthe mounting unit MUT 01 – the fuse bar. The remain-ing sequence varies – refer to the sticker on the top barof the module shelf for the designation.

A rack is a fully equipped, factory-tested production,testing, delivery and installation unit.

Each rack has a fixture for holding the module extrac-tion tool. The holder is located on the right rack uprighton the module side of the rack. It also contains the dis-charge socket for connecting grounding wrist bracelets;a second discharge socket station is also found on therear side of the holder.

Grounding bars are mounted on the left and right up-rights of racks. For surface grounding reasons, the barsare conductively connected along their entire lengthwith the uprights, and therefore with the rack groundconnection. The reference potential, GND, of the logi-cal voltages for all load circuits is connected to thegrounding bars. The grounding bars are connected di-rectly with the positive conductor of the rack rows.

A rack is enclosed on its front and rear sides with a pairof doors and a top section in each case. This producesa cabinet 500 mm in depth (type “A”) and 600 mm indepth (type “ B”). In order to allow unrestricted accessto the units in a rack even in narrow operating aisles,the doors can be opened to 180˚. The doors are perma-nently connected to ground by means of contact strips.

A rack may be covered on the side uprights withscreening walls to protect it against electromagnetic in-fluences. Depending on the cabling, screening combsare arranged in the upper or lower sections of racks toconnect the screening ground for the cables.

Racks are designed in such a way that heat generatedby the operating installed units is dissipated in the am-bient air by free convection. Two types of fans are usedfor racks that generate too much heat.

Racks can be installed either directly on the floor of anequipment room or on a raised floor. Raised floors al-low underfloor cabling as well as direct ventilation to theracks from below. A planar cable shelf is mountedabove the racks for installations without a raised floor.

The left door on the front and back of the rack is labeledwith the device identification and the serial number ofthe device type.

The rack paneling, i.e. the front and back doors as wellas the sides at each end of a row, are made of chromi-um steel. The ochre-colored top panel is labeled withthe system designation.

Each rack is labeled at the factory with the equipmentdesignation and the installation site (room, row, rack).This label is on the front right of the base section.

The rack is designed to allow free convection of dissi-pated heat resulting from operation of the mounted de-vices. This heat is vented to the outside.

Each rack is equipped with a holder for the module re-moval tool. This holder is located on the right upright onthe module side of the rack. The holder also has an in-tegrated discharge socket for connecting the wriststrap.

Simple clamping elements allow fast system installa-tion. They connect the individual racks together to forma rack row while at the same time securing the connec-tion to ground. These connections also serve as bear-ings for the doors.

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CablingAll connecting cables in the network node can beplugged in. As a result, electrical connections can bemade quickly and easily in a rack and between individ-ual racks at the installation site.

Connector cables are multiconductor cables terminat-ed either at both ends or at only one end with cable con-nectors, depending on the application.

Connector cables are usually supplied in standardlengths. They are fully prepared and have been electri-cally tested.

SIVAPAC cable connectors

Cable connectors are plugged at the rear of a shelf di-rectly onto the terminal pins on the blade or terminalstrips. Centering strips on the wiring board – one percable plug-in position – ensure the stability of the termi-nal pins and the correct positioning of the cable con-nectors.

Contact pitch = 5 x 5 mm

SIPAC-N cable connectors (partially shielded)

The cable connectors (1SU, 2SU or 4SU) are pluggedat the rear of the module shelves directly onto the ter-minal pins of the backplane. Interchange connectors onthe wiring board stabilize the terminal pins and fix thecable connectors in the correct position. The contactpitch is 2.5 x 2.5 mm.

SIVAPAC and SIPAC-N cable connectors can be in-serted, locked, unlocked and removed without anytools. Each cable connector has a version with a cableentrance upwards or downwards. Both of these vari-ants have the same parts but with the connector hous-ing turned by 180˚ with regard to the other.

Cable shields make contact on the metal plate of thecable connector. A grounding connection to the moduleshelf or rack is established for a plugged cable connec-tor by means of the contact springs on the centeringstrip or the contact pins in the interchange connector.

Centering strip

Blade stripat moduleframe

Contact spring

Cable Connector

Adapterbridge

Cable connector(partially shielded)

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SIPAC-S cable connectors (fully shielded)

The cable connectors (1/2 SU, 1 SU or 2 SU) areplugged at the rear of the module shelves directly ontothe terminal pins of the backplane. Shielded inter-change connectors on the wiring board stabilize the ter-minal pins and fix the cable connectors in the correctposition. The contact pitch is 2.5 x 2.5 mm.

The cable connectors can be inserted and locked with-out the need for tools. They can be unlocked and re-moved with the aid of an extraction tool.

DistributorsA mini-distribution strip with solder-free clamping con-nection is used as the interface between the subscriberlines in the cable network and any internal line of thenetwork node.

The mini-distribution strip is based on the cost-effectivesolderless IDC method of termination. This method cor-responds to the IEC 352-3 standard (formerly DIN41611, Part 6, Crimped Connections). The mini-distri-bution strip uses a double snap-in terminal elementwhich can be connected with two multiconductor orjumpering wires. A simple termination tool is used topush the wire into the terminal element. This piercesthe insulation of the wire and cuts off the protrudingwire end.

A lasting airtight and electrically reliable contact is thusestablished between the terminal and the metallic con-ductor of the wire. The double terminal uses conven-tional forms of insulation (e.g. PVC or PE) forcontacting wires with a conductor diameter of 0.4 to0.6 mm.

In addition, the terminal guarantees a perfect and se-cure contact even after several hundred terminations.The double terminal element principle allows cables orjumpers to be connected or repositioned without elec-trical interrupting by using separable elements.

For large network nodes, the main distribution frame ismade by setting up one or more basic elements side byside to obtain the required size.

A special wall-type distributor exists for medium andsmall network nodes.

Typical characteristics include the following:– Serviceability: Clearly arranged connection panels

and easy access to all terminals; fast wire connec-tion: clamping wires requires only about 1/3 of thetime needed for wire stripping and soldering forconventional distributors.

– Solder-free insulation displacement connection:contact is made by simply pressing the insulatedwires into the terminals (insulation piercing con-necting devices).

– The twin terminal principle means that cables andjumpers can be activated or switched without elec-trical interruptions using isolating elements.

– Top transmission quality: high-quality materials en-sure optimum values for contact operation and in-sulation.

A main distribution frame (MDF) has a line side and anetwork node side. The bearing element of the MDF isa screw-assembled frame. The line and network nodesides are constructed in the frame with the mini-distri-bution strips.

Two different basic MDF layouts are used horizon-tal/vertical and vertical on both sides.

Adapter bridge

Cable Connector

1/2 SU1 SU

2 SU

Groundingspring

Verticalterminal block

Cableconnectorsocket

Mounting frameandjumper comb

Cable cover

Terminationtool

Over-voltageprotectionconnector

Wireguide

Isolatingplug

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Every access line in the subscriber cable network canbe connected in the MDF with any internal switchingsystem line by means of hook-up lines.

The MDF for large systems is extended by placing ba-sic units in a row to obtain the required size.

A special wall-mounted distribution frame is availablefor medium-sized and small systems.

Power supply and distributionThe required protected supply of normally 48 V or 60 Vdirect voltage is generated from the mains electricitysupply by means of switched-mode rectifiers. The pow-er supply systems with the batteries for energy storageoperate in parallel stand-by mode.

In the case of multifunctional rooms, switched-moderectifiers with a rated current of ca. 30 A and 120 A areincluded in the switching room itself: for small networknodes with a rated current of up to approx. 720 A aswell as containers, in compact power supply systems(complete power supply system in one or two cabinets);for larger network nodes with a rated current of up to2,500 A, in separate rectifier cabinets up to 960 A each.

The other components, such as 2,500 A battery anddistributor cabinets and 300 A or 630 A power distribu-tion equipment, are chosen according to the power re-quirements in the final capacity stage and form part ofthe central power supply systems.

For switching systems with a rated current of above2,500 A, the power supply systems using rectifiersracks for 120 A are installed centrally in enclosed elec-trical operating rooms. Battery and distribution panelsand mains distribution racks complete the installations.

Lineside

180

5 × 180 = 900

290

1 1

2

3

6

7

8

5

4

2900

Switchingside

Verticalterminalblock Horizontal terminal block

dimensionsin mm

MDF side viewNetwork node side view

2

3

4

5

6

7

8

9

10

11

12

13

1

2

3

4

5

6

7

8

9

10

11

12

13

3300

360 460

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In such power supply systems, the batteries are alwayshoused in a separate battery room. If maintenance-freebatteries are used in compact power supply systems,these can be installed in battery cabinets in the powersupply or switching room.

If peripheral devices are to be supplied with protected230 V AC voltage, this is done by means of low-powerinverters supplied with energy from the protected DCvoltage.

DC distribution network

The DC distribution network consists of the main distri-bution lines and the branch distribution lines.

Power fades and excess voltage caused by short-cir-cuits in the distribution network are prevented by takingthe following measures:– Each row of racks has a separate feed line from the

power supply system with an associated fuse(250 A or 315 A).

– Each rack feeder is led through filters and protectedagainst power fades and spikes by means of capac-itors.

– With the exception of the rack for devices (R:DEV),no fuses larger than 10 A are used.

Main distribution lines

The line from the power supply system to the end framein each rack row is known as a main distribution line.For reasons of economy and for ease of installation,flexible standard cables with the following cross sectiondimensions are used: 95 mm2, 120 mm2, 150 mm2.

Up to four cables can be connected simultaneously inorder to comply with the permitted voltage drop. Tokeep the line inductance to a minimum, positive andnegative conductors must be routed in close pairs.

The main distribution lines can be laid above the rackrows or under a raised floor. The lines are always rout-ed to rack rows on the access aisle side.

Branch distribution lines

Within each row, the branch distribution lines are laidover the rack. The positive conductor thereby alsoserves as a mechanical support for the negative con-ductor(s). The grounded positive conductor is made offlat copper (200 mm2), while the negative conductorconsists of an insulated cable (16 mm2) per requiredcircuit per rack. As described above, the positive andnegative conductors are connected to the power distri-bution frame in the end frame of the rack rows.

1.rackrow

n.rackrow

Equipment room

G

Public mains400V / 230V

Battery room

24 cells

Genset

Diesel

ACdistribu-

tion

with

rem

ote

pow

er s

uppl

y cl

uste

r

DC

Battery

Fusing &distribution





PDF (A)






PDF (A)

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An end frame with power distribution frame (PDF(A)) isalways installed for each rack, even if not all the protec-tive switches are used. If more than 32 protectiveswitches are needed for a rack, another end frame withPDF(A) is installed at the other end of the rack. Howev-er, if a Siemens power supply contains an adequatenumber of fuses, e.g. in the case of small RDLUs or a10 ft or 20 ft container, there is no need for a PDF(A) inthe end frame.

Rack power supply

The racks are connected to the branch distribution linesby means of fully insulated special terminals. These ter-minals pierce the insulation to make contact and cantherefore be connected without risk of injury or damageduring operation.

Each rack is equipped in the top front mounting areawith a fuse bar for up to 33 safety fuses or with a break-er panel for up to 28 protective switches for protectionof direct current circuits. From here the voltage convert-ers and load circuits in a rack are individually suppliedwith power transmitted over connectable single lines.

Module converters

Module converters are designed for providing up to300 W of power and up to seven voltages per module.

The secondary operating voltages of the converters aredistributed within a module frame via the frame wiring.

PDF(A) 1

L (+)L (-)

PDF(A) 2

Main distribution line from above

PDF(A) 1

L (+)L (-)

PDF(A) 2

Main distribution line from below

L (-)L (+)

Rack

Fuse bar

GND

F17 F32F01 F16

C

Branch distribution line from the power supply system

2 22 2

GND

Blade SocketGrounding bar

L (-)L (+)

+

Filter

C

+

+UE- UE

GN- UE+UE

GND

+UE- UE

+UE- UE

GN

GN

Module frame

Module frame

Module frame

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Rectifiers

Rectifiers are provided for supplying power to devicesrequiring an alternating voltage of 230 V at 50 Hz –such as PCs, routers and modems mounted in a rack.In large systems, two rectifiers with a rated power of500 VA are used as required. Their dimensions (width:440 mm, depth: 340 mm) are adapted to the standardmodule frame size. They have a height of 110 mm.

Grounding

Grounding bars are mounted on the left and right up-rights of the rack (type “A” and “B”). For surface ground-ing reasons, the bars are conductively connected alongtheir entire length with the uprights, and therefore withthe rack ground connection. The grounding bars areconnected directly with the positive conductor of therack rows. The reference potential, GND, of the logicalvoltages for all load circuits is connected to the ground-ing bars.

The positive conductor of the power supply for the con-verters is fed to the module shelves separately from thefuse bar. The racks are also connected with the planarcable shelf used for the cabling.

If the cabling in a system is laid under a raised floor, anetwork of aluminium strips is laid in a 60 cm x 60 cmgrid pattern. Each rack is connected to the network. Po-tential equalization of very low impedance is obtainedwith the racks and the parallel, grounded power supplyleads.

This grounding network is not required in systems withcabling over the planar cable shelf. In these cases theelectrical properties of the shelf have to match those ofthe grounding network. The gap for the tubes of the pla-nar cable shelf running vertical to the rack rows is re-duced to 410 mm. Cable shelves used also forelectrical connection between the network node orswitching equipment and the main distribution frameare connected with good conductability either with thegrounding network under the raised floor or with theplanar cable shelf.

The entire system grounding connection is combinedwith the common ground for the building.

Installation recommendationsNetwork nodes can be installed in any building, even instandard buildings, and if necessary together with ex-isting equipment from other systems. There must, how-ever, be a recommended height of 2,900 mm as well asthe required floor support capacity.

With a raised floor, the recommended room height is3,200 mm.

The length of the rack rows depends not only on theshape of the room itself but also, and in particular, onthe dissipated heat. In conventional buildings (withouta raised floor), where air must be supplied from theside, up to 9 racks can be placed in a row if the buildinghas ventilation and air conditioning without cold air; upto 12 racks can be lined up in buildings having ventila-tion and air conditioning with cold air.

When the racks are installed on a raised floor, a maxi-mum of 16 racks are permitted in a row.

The standard distance between row fronts is1,200 mm, and the aisle between the rows is 700 mmwide.

If the rack rows are further apart, the heat load per sur-face unit of the network node room is reduced.

The racks are delivered to their place of assembly al-ready fully equipped with frames, modules and voltageconverters. The rack is delivered ex-works withoutcladding but with transportation protection covering themodule side, the wiring side and both side sections.This transport cover turns an equipped rack into a rigidpackaging and transportation unit. The transport cover,including the front and rear panel, should not be re-moved until the rack has reached its final place of in-stallation within the network node.

Planar cable shelf

min.300

2900

2655

2450

2900

2655

2450

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Depending on the conditions of transportation, a con-ventional outer crate can also be used.

When the network node is installed, the factory-mount-ed transport cover remains on the rack until the basicinstallation tasks have been completed. This protectsthe module and wiring sides.

A trolley is used for transporting the racks within thenetwork node room. This contains jacks which can beused to lift the rack and push it with minimum force toits place of installation. It is also possible to positionracks in gaps in the rack row.

The network node is set up in the following order:– Installation of all racks– Protective measures against earthquake damage

(if necessary)– Pre-assembly of protective shielding panels– Interconnection of racks– Connection of each rack to the grounding network– Assembly of end frames (both sides)– Low voltage supply to rack rows– Cabling rack internally– Cabling between individual racks– Cabling between individual rows of racks– Installation of the connection grid– Installation of the MDF– Installation of the cable route to the MDF– Connection of cable routes and the MDF to house

grounding– External cabling of DLU – MDF; LTG – DDF– Preliminary testing of the external cabling– Installation of lighting and 230 V connection– Installation and cabling of special equipment– Complete system shielding– System labeling– Final testing of the external cabling– Final installation inspection– Completion of “red folder” (documentation on all

modifications made since completion of the plan-ning documents).

Raised floors

Siemens network nodes allow a high degree of concen-tration of hardware in a minimum of space. For full uti-lization of the installation space in a switching room,high change-of-air values are required to ensure heatdissipation. The optimum solution is to install theswitching equipment on a raised floor and to introducethe appropriate volumes of air required for ventilationunder the raised floor. Raised floors allow the inlet of airover large areas into a network node at low air speedand the guidance of air directly to enclosed racks fromunderneath. Moreover, the space under raised floorscan be used for cabling of the network node, thus doingaway with the need for a planar cable shelf.

Raised floors should have a standard tile size of600 mm x 600 mm. A raised floor height of 400 mm isrecommended. Openings are cut out of the tiles underthe racks for air and cables. The holes are cut in sucha way that cables can be freely laid without the need offeed-throughs once the flooring tiles have been re-moved.

An earthquake-secure raised floor model is availablefor use in network nodes in earthquake-endangered ar-eas. The rack rows must be anchored to this floor.

Load-bearing capacity –surface load: 1000 N/m2; concentrated load:5000 N/flooring section

Rack row connection

When installing systems using raised floors, the rackrow connection improves the mutual support of the rackrows. The rack row connection is a system of longitudi-nal and cross sections fastened on the head of theracks.

The longitudinal profiles between two rack rows areused for attaching the rack row illumination system.This arrangement guarantees optimum illumination ofthe racks.

Raisedfloor

Cables

SupportFloor

Rack row divisionmin. 1,200 mm

Cable entrymin. 300 mm

Flooring tile size:600 mm

Air inflow

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Planar cable shelves

When planar cable shelves are used, the connector ca-bles are guided upwards and held in a screening comb.Spring-loaded clamps relieve strain on the cables.

Cabling

The cabling within the various rack rows, the connec-tion of rack rows with each other and the routing of ca-bles to the distribution frame comply with thecustomer’s requirements. The cabling is guided eitherin planar cable shelves on top of the racks or under-neath raised floors.

Container network nodesNetwork nodes are installed in containers for mobileapplications. Containers are available in three differentsizes (10-, 20- and 40-foot).

These mobile network nodes can be integrated into ex-isting networks for local and long-distance traffic withina very short time. The containers take up little spaceand are modularly and flexibly adapted to the require-ments of individual applications. Containers can alsobe connected together to form so-called “container vil-lages”.

Container housings are EMC (electromagnetic-compli-ant) and protected against splash water.

Racks, without outer covers, in a container can be eas-ily accessed from both sides. The racks are mountedon rubber-metal mountings for protection againstshocks and impact during transportation.

The racks installed in containers dissipate their heat inthe container air. Air-conditioning equipment extractsthe heated air through openings in the front of the con-tainers, cools the air and re-introduces it into the con-tainers (circulating air method). The coolingperformance of the air-conditioning system is adjustedto the size of the container and the climatic conditionsin the country. The air-conditioning equipment is in-stalled in a separate generating room in compliancewith the ISO container dimensions.

A duplicate standby air-conditioning system is providedin order to ensure continuous operation of the switchingsystem.

Containers are preferably mounted on concrete groundtables.

Basic frame

Screeningcomb

Planar cable shelf

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SheltersShelters are offered in four variants (150, 400, 700 or1000).A DLU in a shelter is particularly well suited for rural ar-eas with low numbers of subscribers. Shelters are de-signed as double-sided aluminium constructions andare robust, weather-resistant, splashwater-proof andsealed against dust in compliance with IP55. They arealso tested for compliance with EMC (electro-magneticcompatibility) specifications. A heating unit and fanmodule mean that the shelter can also be installed out-doors or in any room

The wide-opening swing doors at the front allow full ac-cess to the functional units. Once opened, the powersupply units and shelves in the switching system canbe accessed for service and maintenance purposes.

The door on the left side opens up the main distributionframe (MDF) with integrated lightning module and thespace for incoming subscriber and power supply lines.

Shelters are mounted on concrete foundations for pro-tection against earthquakes.

Technical data

Module dimensions(without frontpanel, connectors andother board mounted components)

height = 230 mm,width = 7 x 5 mm /12 x 5 mm or 14 x 5 mm,depth = 277 mm

Fan box dimensions height = 300 mm,width = 750 mm,depth = 375 mm

Fan tray dimensions height = 90 mm,width = 750 mm,depth = 300 mm

Voltage range of fan box / fan tray 37.5 - 75 V

Rectifier dimensions height = 110 mm,width = 440 mm,depth = 340 mm

Rack dimensions (type ’A’ / type ’B’) height = 2450 mm (8 ft.) /2130 mm (7 ft.),width = 770 mm /880 mm,depth = 460 mm (withoutcladding) / 500 mm (with)/ 600 mm (with cladding)

Internal rack dimensions(available for mounting of subracksand internal cabling)

height = 1948 mm (7 ft.) /2268 (8 ft.),width = 778 mm,depth = 540 mm

Weight of the equipped rack 150 kg up to 350 kg

Copyright (C) Siemens AG 2002

Issued by Information and Communications Group • Hofmannstraße 51 • D-81359 München

Technical modifications possible. Technical specifications and features are binding only insofar as they are specifically and expressly agreed upon in a written contract.

Order Number: A30828-X1160-P100-1-7618 Visit our Website at: http://www.siemens.com

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Mechanical Design