Stockman Arne Wallers Ericsson have developed cabinet-based equip

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

Stockman Arne Wallers Ericsson have developed cabinet-based equip

Datasheet Thumbnail

Top Searches for this datasheet

metric equipment practice
Stockman Arne Wallers
Ericsson have developed cabinet-based equipment practice called that intended public telecom sites customer sites private networks. Applications range from small access units large switches powerful processors. authors describe most prominent features compared with existing equipment practices: compliance with metric standards from ETSI, excellent characteristics.
only does equipment practice make literal framework telecommunications system, provides framework basis physical properties system well, including such obvious features dimensions, weight, cooling performance. Less obvious, perhaps, environmental properties equipment practice that associated with production, installation, operation, scrapping. These properties (electromagnetic, seismic, chemical, etc) normally specified international, regional national standards. equipment practice synthesis these external requirements requirements that were derived from system design process. Mechanical interfaces, example, must harmonised with corresponding system interfaces.
Main characteristics
Standards
Figure equipment practice fulfils metric ETSI standards excellent characteristics.
Abbreviations
Electromagnetic compatibility Electromagnetic interference Electrostatic discharge European Telecommunications Standards Institute International Electrotechnical Commission Plug-in unit TS-HOD Two-step high-ohmic distribution Versa Module Eurocard ETSI
equipment practice complies with metric standards according International Electrotechnical Commission (IEC) European Telecommunications Standards Institute (ETSI), Bellcore standards have also been considered. Compliance with internationally recognised standards foundation open mechanical interfaces 501. open mechanical interface offers important advantages: different subsystems, including 19-inch subsystems, mixed matched; short time customer; sourced products, based standards such Versa Module Eurocard (VME) CompactPCI, easily accommodated; Ericsson subracks mounted existing 19-inch racks cabinets customer's site with little adaptation. Details cabinets, subracks plug-in units (PIU) provided this article.
Electromagnetic compatibility
main objectives developing create system with excellent electromagnetic compatibility (EMC). EMC, which area ever-increasing importance, defined ability equipment function satisfactorily electromagnetic environment without
Ericsson Review 1997
introducing intolerable electromagnetic disturbances that environment. EMCrelated requirements legislation will have great influence current future hardware designs. fundamental principle hardware design calls interference neutralised close source possible. adhering this principle, electrical designers able avoid most EMC-related problems. means shielding subracks, cables, plug-in units components, equipment practice further improves system's characteristics. connection cable shields front plug-in unit extremely important system's performance. keep cable from acting antenna radiation from system, maximum impedance less than inductance). Similar requirements apply earthing filters unshielded cables. requirements shielding have been imposed cabinets. Instead, shielding functions have been allocated subrack level. There main reasons doing subracks installed customer cabinets meet requirements without need further protection; cabinet doors opened during maintenance work without causing stipulated emission limits exceeded. shielding concept illustrated Figure subrack shielding efficiency least frequencies GHz. Gaskets that block electromagnetic interference (EMI) placed between board front panels, thereby maintaining closed subrack shield. Shielding covers provided individual components board level. Verifying measurements taken delivered products show that design fulfils, with ample margins, requirements according Class Electrostatic discharge (ESD), which transfer electric charge, represents EMC-related problem special concern. Unless this phenomenon properly dealt with, cause considerable maintenance problems. Thus, following measures were taken have been prescribed working with 501: basic protection, mechanical parts low-inductively connected earth; electrostatic discharges diverted
Ericsson Review 1997
Subrack view
Backplane Subrack shield Backplane connector Plug-in unit
Shielding Component front panel shielding cover Shielded cable gaskets connector between front panels
Figure shielding concept. Shielding functions allocated subrack level.
through high-ohmic wrist-straps, which worn maintenance personnel connected mechanical structure cabinets.
Signal transmission
Multilayer-printed-board technology high-speed communication high signal density been applied. printed boards minimise supply-voltage ripple make radiated emission. Shielded front cable connectors were developed power, twisted pair coaxial cables. Each these connectors been verified terms performance. signal transmission, grid metric connectors used between plug-in units backplane. connectors available standard low-cost models high-performance shielded models with controlled characteristic impedance.
equipment practice complies with following international standards
917-2-1 Interface coordination dimensions equipment practice. Detail specification cabinets racks. 917-2-2 Detail specification equipment practice. Dimensions subracks, chassis, backplanes, front panels plug-in units. ETSI 119-2 Engineering requirements racks cabinets.
Cabinet side view showing uppermost subracks flow
Cooling
Cabinet rear side
Chimney
Figure principle parallel cooling. Each subrack separate inlet room temperature.
guiding plate
Cabinet side view
Ordinarily, cooling capacity customer's premises determines much power dissipated cabinet. Some common maximum values singledepth cabinet 1000 doubledepth cabinet. However, because higher levels accepted some applications, engineers designed equipment practice accommodate maximum cooling capacity that considerably higher than these values. Natural convection cooling preferred choice applications. Forcedconvection cooling (fan cooling) allowed only when technical solutions required provide natural convection unreasonably complicated. Either parallel serial cooling used 501. principle parallel cooling certain advantages, Figure example, since each subrack separate inlet room temperature, parallel cooling method: facilitates higher plug-in unit heat load; permits each subrack cabinet configured independently; greatly improves fire resistance, preventing fire from spreading from subrack another. Parallel cooling preferred cooling method used natural convection. However, cooling, serial cooling method preferred. Figure shows examples cooling techniques used single- double-depth cabinets. Several configurations possible, including those that combine natural convection cooling same cabinet.
Power distribution earthing
power distribution, normally employs technique known twostep high-ohmic distribution (TS-HOD), which minimises effects shortduration voltage transients (spikes) produced short-circuit currents. Cabinets subracks designed sustain external fault currents 3000 difference earth potential between subracks less than within subracks difference less than
Environmental management production
Figure Examples cabinet cooling. Left: parallel, natural-convection cooling single-depth cabinet. Right: serial cooling.
recent years, environmental management with emphasis scrapping, recycling environmental load become imporEricsson Review 1997
tant issue Ericsson. Thus, when selecting materials assembly methods that went into making 501, designers were careful ensure that they fulfilled existing well anticipated requirements this field. What more, designers specifically chose materials production methods that could obtained used produce mechanical structure practically part world.
Handling installation
Front view
Overhead cabling
Floor cabling
driving forces behind development need shorten installation time, which part overall requirement short time customer. This requirement ways: Mechanical endurance characteristics permit fully equipped tested cabinets delivered installation site. Earthquake resistance maintained without requiring additional strengthening elements. time needed install cables reduced substantially. Thanks design 501, external cabling installed cable distribution system before cabinets delivered site. Prefabricated cable sets readily plugged into cabinets. cabinet design allows external cables installed without feeding them through holes rack.
Cable distribution system
view
Figure Cable pathways cabinets: vertical cable ducts access cable distribution system; short, straight cable paths between adjacent cabinets.
Vertical cable ducts
Ericsson cable distribution system mounted either above equipment cable trays, below equipment raised floors. Moreover, different cable types separated: Optical fibre cables, which usually sensitive mechanical stress, require separate routes. power cables separated from signalling cables order meet customer safety requirements. Existing customer cable distribution systems used instead supplied Ericsson.
Cabling cabinets
between adjacent side-by-side back-toback cabinets. Ordinarily, cables connected directly front panel plug-in units. However, system parts with extensive cabling, additional methods used connect cables from back. method, which mounts connectors directly backplane, intended mainly internal cabling between subracks within same subsystem (Figure left). second method, which uses connection plug-in units that located back main subrack (Figure right), best suited interfaces that require different types connector. Other methods apply when cabinets other systems/subsystems electrically optically interconnected.
Figure Left: subrack with direct backplane connections. Right: subrack with connection plug-in units.
Side view
Side view
Figure shows cabling routes between adjacent cabinets. Cables between cabinets usually vertical cable ducts mechanical cabling structure above below cabinets. high-performance systems, short, straight cable paths arranged
Ericsson Review 1997
Transit connectors
Cable cover
Transit connectors Connection
Cable cover
designed make operation maintenance procedures simple self-explanatory possible. Every unit that have disconnected replaced labelled with product identity that includes product type number. label information presented both alphanumeric bar-code form.
Dimensions
Cabinets
Figure Cabinet height 2200/1800 width With depth with
Figure Cabinet height 2200/1800 width mounted together with four gives deep cabinet.
Cabinet
Basic parts cabinet make-up Cabinet frame Door Side cover Back cover Back cover Side cover Back-to-back mounting
shows different ways combining elements cabinet. Only outermost cabinets multi-cabinet system equipped with side covers. Back covers used only single in-line configurations. normal aperture width This dimension, which gives ample space vertical cabling, metric standard equivalent 19-inch standard. mounting plates cabinet also mounted form aperture width which complies with European telecommunications standards (ETS). Figure shows mixed configuration single-depth back-to-back doubledepth cabinets.
Subracks
Figure Cabinet height 2200/1800 width mounted together with four gives deep cabinet.
Back-to-wall
Back-to-back
Doubledepth cabinet Free-standing single
Singledepth cabinet
range subracks available different system needs. standard subrack, which wide, houses plug-in units with spacing. small subsystems, such compact central processor AXE6, special half-width subrack provides complete redundancy without wasting valuable space. subracks have height modularity that they 150, 300, high. Different kinds plug-in unit mixed same subrack. accordance with 917-2-2 standard, plug-in unit widths steps subracks shielded meet requirements EMC. Besides normal subracks housing plug-in units, fan-unit subracks, guides other accessories also available. Note: term subrack used international standardisation; however, documentation often uses term magazine.
Plug-in units
Figure Floor plan telecom centre showing possible arrangements cabinets.
Different types plug-in unit (PIU) inserted into subracks. most
Ericsson Review 1997
common type consists single printed board assembly (ROJ 207+). Several types composite plug-in unit have also been defined (BFB 301+) combinations more boards single unit. same size applies both plug-in units,
Plug-in unit
following dimensions have been defined mm):
dimensions
Backplane
Conclusion
Ericsson's cabinet-based equipment practice which complies with metric standards from ETSI, offers important advantages compared with other equipment practices. example, easily accommodates other, standardised products; Ericsson subracks mounted existing cabinets customer's premises; excellent characteristics provide superior protection subracks, cables, plug-in units, components. Moreover, thanks modern, wellplanned design, enables operators installation time substantially. external cabling installed cable distribution system before fully equipped tested cabinets arrive. When cabinets delivered, prefabricated cable sets readily plugged into them. materials assembly methods used were carefully selected with fulfilling existing well anticipated environmental requirements.
H=115 H=265 H=265 H=265 H=415
D=175
D=175 D=225 D=300 D=175
References
917-2-1: Interface coordination dimensions equipment practice. Detail specification cabinets racks. 917-2-2: Detail specification equipment practice. Dimensions subracks, chassis, backplanes, front panels plug-in units. ETSI 119-1: Introduction terminology. ETSI 119-2: Engineering requirements racks cabinets. ETSI 119-3: Engineering requirements miscellaneous racks. Lundqvist, hardware evolution. Ericsson Review (1997):2, 52-61.
Figure subrack with full-size half-size plug-in units.
Ericsson Review 1997

Stockman Arne Wallers Ericsson have developed cabinet-based equip

Top Searches for this datasheet

Other recent searches