Filename: ISDN.DOC
Uploaded by: Doc Telecom /#66/
Uploaded on: 18 Jul 88 20:59:20 Monday
---------------------------------------------------------

 *********************************************************************  *                                                                                                Doc Telecom                                     *
 *                                                                   *
 *                           presents                                *
 *                                                                       * *                   THE TRUTH ABOUT ISDNs                              *
 *                                                                   *
 *********************************************************************


 What's an ISDN ?, is that what you wanted to know well, he defintion for  ISDN i Intergrted Servces Digital Networks. All of things out there seem to b quasi-ISNs. For eample man networksprovide itergrated services over a common digital network i some fashon,like a acket swithing publi data netwrk that provides lots of diffrent services, (ike electroc mail ,ect and all ofthem providd on a commn backbone , you would think surly this ualifies as ntergrated Srvices, sinc data is trasmitted, sury this must be a Digital Network, bt noooo!, tha is just a lage misconn-
cption. For th network to b a true ISDN, it must:
 
1) Prvide multiple ervices
2) Offr digital intefaces to usersand other netwrks based on ISDN stand-   ards. <more o these later>.
 
 What are theattributes of IDN ?
 --------------------------------

 In ISDN thrteen attributesdefine a bearer ervice, broken ito three groups,these attribute are as follows..
 
 Information Tansfer attributes ------------------------------
 1 Informatin Transfer mode
 2 Information Transer Rate
 3> Informtion Transfer Capaility
 4> Structur
 5> stablishment of Comunication
 6> Commuication Configuratin
 7> Symmetry
 
 Acess attributes
 ----------------------------
 8> Access chnnel and rate
 9> a.Signalling access prtocal
 9> b. Infrmaton access protocl

 General attribute
 ------------------------------
 10> Suppementary serices provded
 11> Quaity of Service
 12> Inerworking possiblitys  13> optional and commrcial

 
 Circuit-Mode 64-Kbps Unrestricted, 8-khz Stuctured
 --------------------------------------------------
 
 The cucuitmode, 64-kbps, unrestriced, 8-khz structured beaer service provides inforansfer between users wi out any change in bit steam. Users may choose anyapplication for this bt sream, including there wn rivate submultiplexingsystem.(for example 2 PABX <privated automati branchexchange> may use tis servce to transmit, two32kpbs ADPCM voice channelsect).
 The phras "8kz stuctred" is refered o the inhernt stucture of te info transfered by an ISDN When one use transmits infoto another usr, the transmiton is accompaied by 8kz timming info.This akes it posible for users to xchange chracters,8 bit sampls,ect. Witout a user-to-user sychronizaton schee within the circuit.

CircuitMode, 64-kbps, 8khz strctered,Usable for speech
 ______________________________________________________

 This is used for peec bearer service and is similar t he previous one, except that ISN assume the information in the icuit is human speech. An ISDN ma oute such a connection in any fahon appropriate for speech - evenoer analog lines.

 Circuit-Mde, 4k bits, 8khz Structured, Usabe fo 3.1 khz 
 Audio information tansfr.
 ---------------------------------------------------------
 
 This differs from the one abve becase this service suport a "3. khZ 
 audio" rather than peech. Cals with this service may berouted ove analog circuts, and the ntwork still performs conersion betwee digital incoding laws.
 A speech cal may als be routed over pecial multiplexing sytems, such as TAI (Time-assignned speeh interpolation) whch uses bursty charcteristics of human peech to squeeze moe conversations on agiven transmissionsstem.
 By distinguising speech and audo bearer services, thenetwork can more esily route each all though the appropriae transmition failties.


 Essential bearr services
 ------------------------------------
 o  Circit-mode, 64kbp, 8khz structured, unrestriced
 o  Circuitmode, 64kbps 8khz structured speech
 o  Cicuit-mode, 6kbps, 8khz structured, 3.1 khz udio
 o  Pacet-mode, vrtual call and permant virtual cicuits
 
 Aditional bearer services
 ------------------------------------
 o Circuit-mode alternatespeech/6kbps non speech, 8khz structured
 o Crcuit-moe, 384kbps, 8khz structured unrestriced
 o Cicuit-mde, 1536-kbps, 8-khz structured, unrestrcted
  Ciruit-mode, 1920-kbps, 8khz, structure, unretriced
 

 Well I hope this provides to be usefl, de o the fact I lost my fucking referece matrialThs phile ias uncompleted, but I hope it has som us..
  
  
 Doc Telecom



Enter the number to ea(Q=Quit ?=Menu):