remote axe 10 subscriber switch in a container an optical fibre line ...

More documents

Recommendations

Info

An Optical Fibre Line Systemfor 34 Mbit/sTommy Jansson and Bo StjernlofThis article introduces Ericsson s digital line system for optical fibre cable.ZAM34-2. The transmission rate of the system is 34 Mbit s. which corresponds to480 PCM coded telephone channels. The system meets all relevant CCITT andCEPT recommendations. It is primarily intended for use in urban networks, e.g.as the transmission link between exchanges or between an exchange and anumber of remote concentrators or as an entrance link to a radio relay link. Thesystem is available in two versions, one with a laser transmitter and the otherwith a light emitting diode (LED) transmitter. The laser permits a repeaterspacing of 12km as against 5 km for the LED. However, the LED version offersgreater reliability.fibres having an attenuation of 3-4dBper km and a bandwidth of 300 MHz • kmat a wavelength of 850 nm.The small spectral width of the laser,together with the large bandwidth of thegraded index fibre, result in negligiblematerial and mode dispersions in thelaser system, e.g. the system is limitedby the attenuation. Because of the relativelylarge spectral width of the LED,the limitations of this system, is set bythe material dispersion of the fibre.UDC 621.315:535 394621.391.63Fig. 1The equipment in the 34 Mbit/s systemLDM Line terminating magazineFDU Fault detector unitFDS Fault detection shelfSCS Service circuit shelfST Service telephoneCTB Cable terminating boxD3 34 Mbit/s interface, CCITT G.703 8F3 41 MBaud optical fibre interfaceAL Alarm interfaceDuring the years 1977-1979 a 34 Mbit/sline system for optical fibre, ZAM34-1,was developed for field trials. The purposeof this system was to give Ericssonand the telephone administrations theopportunity to gain experience of digitalline systems for optical fibre cable. Anumber of such systems have been deliveredto various users, and today severalare in regular operation. The newline system, ZAM34-2, is to a great extentbased on the experience gainedduring the design and installation ofZAM34-1 field trial systems 45 .Line system ZAM34-2 with a transmissionrate of 34.368 Mbit/s is intended fordigital transmission of 480 PCM codedtelephone channels over fibre cable.The light source used is either a laserdiode or a light emitting diode (LED),and the photo detector is an avalanchephoto diode (APD). The transmissionmedium is a cable with graded indexZAM34-2 offers the following advantages:- laser or LED transmitter. The latter,which could be used for repeaterspacings less than 5 km, offers higherreliability and lower costs- large repeater spacings, 12 km withlaser transmitters- thermoelectrical cooling of the laserdiode for maximum reliability- modular structure. The system caneasily be converted from a shortwavesystem for 850 nm to a longwave systemfor 1300 nm by changing thetransmitter and receiver units- simple connection to the fibre viaplug-in optical connectors which donot require any subsequent adjustment- flexible mechanical constructionusing Ericsson's BYB constructionpractice, which simplifies installationand handling. All connections aremade with connectors on the fronts ofthe units
TOMMY JANSSONBO STJERNLOFFibre optics andline transmissionTelefonaktiebolaget LM Ericsson- the same magazine is used for the lineterminal and the intermediate repeater,which makes it easy to change theequipment over from termination tothrough-connection- fault location function and facilitiesfor connection to Transmission MaintenanceSystem ZAN 101System characteristicsThe interface for the 34 Mbit/s line systemis D3. and is in accordance withCCITT Rec. G.703. An 8/34 Mbit/s or2/34 Mbit/s multiplexer, e.g. Ericsson'sZAK 120/480' orZAK30/480'.oradigitalradio relay link can be connected to thisinterface.- fault detection equipment for remotesupervision of line terminals and intermediaterepeaters- two or four-wire service circuit equipmentin the terminal bay, and connectionpoints in the intermediate repeatersfor a service telephoneThe incoming line cable isterminated ina cable terminating box, where thefibres are distributed to the different systems.In the box the fibres of the linecable are welded to the fibres in the baycables. The other ends of the bay cablesare fitted with plug-in optical connectors,for connection to the transmitterand receiver units of the system inquestion.Fig. 2Block diagram of the line terminating magazineAISDCLCELCEILSRLSTLDDPFLD3Alarm indication signalData channelLine code error detectionLine code error injectionLoss of signal, receive directionLoss of signal, transmit directionLaser diode degradationFailure of local power supplyLine system ZAM34-2, fig. 1, comprisesline terminals and two-way intermediaterepeaters for transmission over opticalfibre cableThe equipment is normally mounted inM5/BYB bays and consists of- line terminating magazines, LTM,where the signal is recoded, the jitteris reduced and the line is supervised- locally powered two-way intermediaterepeaters that regenerate the signalat regular intervals along the fibrecable- a cable terminating box (CTB) forconnecting the fibres in the line cableto the fibres in the bay cablesAny copper pairs in the fibre cable canalso be terminated in the cable terminatingbox.The equipment is easy to install and haswell defined internal interfaces TheBYB magazines are delivered with theunits in place and with all external connectionson the front of the units. Theequipment is strapped for the most commonapplication, and only a minimumnumber of straps have to be made duringinstallation.Terminal equipmentLine terminating magazineThe main functions of the line terminatingmagazine, LTM, fig. 2, are to- adapt the signal in the send and receivedirections between the D3 interfacestandardized by CCITT for34 Mbit/s and the optical fibre interfaceF3- detect and indicate alarms.The basic version of the line terminalconsists of seven printed board assemblies:- interface unit- line coder- laser or LED transmitter- APD receiver- line decoder- alarm unit- d.c./d.c. converterfor±5Vand ±12V.In the receive direction of the interfaceunit the HDB3 signal from the D3 interfaceis equalized for the attenuation ofthe connecting cable (max. 12dB at
Page 1: ERICSSONREVIEW41982REMOTE AXE 10 SU
Page 4 and 5: ;2Remote AXE 10 Subscriber Switchin
Page 6 and 7: Fig. 3The container is brought out
Page 10 and 11: Fig. 3Repeater spacings and hardwar
Page 12 and 13: 182The primary alarms are those rec
Page 14 and 15: 184Technical dataDigital interface
Page 16 and 17: Fig. 2, leftThe transmultiplexer as
Page 18 and 19: 188Fig. 9Synchronization of the tra
Page 20 and 21: Fig. 13The M5/BYB bay equipped with
Page 22 and 23: Fig. 17ZAJ 5x24/2x60, transmultiple
Page 24 and 25: ERITEX10 for Teletex and WordProces
Page 26 and 27: Fig. 5The central processing unit i
Page 28 and 29: 198Fig. 8The floppy disc unit with
Page 30: 200- finding space for a document o
Page 33 and 34: Local Area Radio System-LARSHans Li
Page 35 and 36: Fig. 5One of the thick film hybrids
Page 37 and 38: 207Technical data for LARSSelective
Page 39 and 40: 209BERTH EKLUNDHDAVID RAPPDepartmen
Page 41 and 42: 211over, the type of traffic handle
Page 43 and 44: 213Models of CPA comparison between
Page 45 and 46: ETable 2The table shows the differe
Page 48: ERICSSONISSN 0014-0171 T E L E F O

remote axe 10 subscriber switch in a container an optical fibre line ...

Create successful ePaper yourself

Delete template?

Save as template?