Eicon Networks ISDN NT1 Specifications

ISDN: Theory & Practice Basic Concepts...

10 arrived. It is his responsibility to understand this and to take appropriate action. Normally this will be done in software such as MLPPP. Summar

11 7. If two ISDN channels are used together, each connecting the same pair of users, how many calls are being made? Two. Even though the calling par

12 ISDN Networks In this section you will learn • How ISDNs are connected together • How users are connected to a public ISDN through an ISPBX •

13 The real (physical) users connect with the network inside the ISPBX over their D channels. If they need to communicate with the public ISDN networ

14 As far as the interface to the public network is concerned, however, the network simply sees the ISPBX as single user with multiple channels avail

15 Bearer Capabilities In this section you will learn: • Bearer Capabilities in depth • The significance of Bearer Capabilities in diagnosing pro

16 • Do all the ISDN networks traversed by the call support the requested Bearer Capabilities? • Does the PBX equipment at each end support these

17 PBX manufacturers often extend or amend the rules for internal ISDN communications, so the cause code returned may not be exactly the same as the

18 Voice, Fax, and Modems In this section you will learn about • How ISDN and analogue networks interact • Digital and analogue conversions in th

19 The analogue signal originating in the microphone of the telephone handset is sampled and transformed into a stream of bits (64 000 of them every

2 Basic Concepts In this section you will find out: • The definition of ISDN • Basic Rate and Primary Rate ISDN • What an ISDN line provides to

20 Analogue fax and modem over ISDN Another important idea is introduced here; this is the Terminal Adapter. A Terminal Adapter (TA) is always neces

21 This would appear to present no problem for the ISDN which is digital and can therefore carry the data passed into the modem (which is digital as

22 Soft-fax and Soft-modem This means that an ISDN adapter with an on-board DSP can also communicate with any device that contains a modem. In the

23 • Modems and CODECs always work in pairs - they can be nested together but each must have a partner. • A Terminal Adapter is an interface betwe

24 6. Does a Terminal Adapter always contain a Codec or Modem? A Terminal Adapter does not necessarily need to have a CODEC inside it. For example,

25 Terminology In this section you will learn: • The naming conventions used within ISDN • The essential difference between the key items • The

26 The NT1 Plus or Super NT1 The 'NT1 Plus' or 'Super NT1' provides additional services to the user by incorporating one or mo

27 Reference Point T is on the user's side of the network termination and allows a single TE or TA to be connected. Reference Point S allows mor

28 It is therefore necessary for the user's own NT1 to be connected to reference point U. This will be necessary if the user wishes to attach m

29 4. What is the name of the reference point that is located on the user side of an NT1? The reference point on the user side of the NT1 is called R

3 What does ISDN give you? - 1 There are two forms in which ISDN is supplied. Basic Rate • Access to the network is called Basic Rate Access (BRA)

30 Device Addressing In this section you will learn: • Why a device needs a unique address • What the address is used for • Forms of address ma

31 In this case, the device which currently has no address is able to request one from the network. The network responds with an address for the dev

32 However, before a device without a TEI can answer a broadcast (to answer an incoming call, for instance), it must request and receive an address i

33 Call Setup In this section you will: • See the step-by-step process for establishing and disconnecting an ISDN call • See the exchange of mess

34 It is mandatory to specify the Bearer Capabilities in a SETUP. Although an initial SETUP would normally specify the destination number for the cal

35 Frequently, delivery of the calling (origin) number is an extra service from your service provider that you have to pay for. This service is often

36 Finishing a call Call disconnection also occurs through messages sent on the D-channel. The message which conveys this information is the DISC,

37 When there is more than one device capable of receiving the incoming call at the destination, a mechanism exists to ensure that only one device ca

38 Connection collision What happens if more than one device attempts to answer the call at the same moment? The CONN messages collide in the D c

39 2. What channel does the end-to-end connection use? End-to-end communications are carried on the B Channel. 3. What is the initial call request

4 • Network Services define how the user and the network interact with each other in order to manage calls. • The user can use Network Services to

40 Managing inbound calls In this section you will learn: • How to manage more than one device on a single ISDN line • How to ensure that the app

41 • PC doesn’t answer because the are no programs running that are listening for incoming calls However, there is a potential pitfall in this solu

42 In this case, the destination fax machine will not answer the call as it is configured to accept only analogue calls. In practice, a device can on

43 1. What must each SETUP message contain? Every SETUP message must also carry a Call Type. This provides information about the contents - such as

44 Rate Adaption In this section you will: • Learn the difference between asynchronous and synchronous data streams • Understand how they can be

45 Bit stuffing The bits required to fill up the 64kbps channel must be added in a systematic way so that the receiving device can remove the bits u

46 Many Terminal Adapters support protocol conversion between synchronous PPP and asynchronous PPP. These protocols are not identical and conversion

47 Cabling In this section you will learn about • Wiring requirements for BRI and PRI • Maximum cable lengths • How to connect several devices

48 If you are connecting only one device to your BRI NT1, the cable can be as long as 1 km if you are using Category 5 twisted pair. In practice, i

49 Another form of wiring is known as the extended passive bus. In this case the total maximum distance allowed is greater, up to about 500 metres,

5 B & D channels In this section you will learn • What the B and D channels do • How the B and D channels share the line • How the structur

50 the user's local power supply has failed. Contrast this with PS2 where the NT1 provides this power from its own mains plug. If none of the e

51 This also shows how you arrange the wiring for the short and long passive bus configuration. If you also need the power supplies PS2 and PS3, you

52 More Termins http://www.freesoft.org/CIE/Topics/index.htm Analogue What does "Analogue" mean? Often this refers to a quantity that

53 Protocol A protocol describes a procedure. When you declare your taxes, you complete a form. There will be boxes on this form where you state y

54 Remember that MLPPP is not the same two separate PPP links. MLPPP is a single connection which uses more than one data link. Two PPP connections

55 The bearer capabilities are communicated to the destination, so that he may act upon them. For example, an analogue call could be presented to a

56 Synchronous and Asynchronous PPP Synchronous and asynchronous PPP are basically the same, but they are not compatible with each other. Both can

6 B & D channel characteristics An ISDN channel has two and only two ends. B channels terminate at a user. A B channel can therefore connect two

7 Notice that there is one timeslot which has no channel assigned to it. This is reserved for your network supplier to use for diagnostic purposes. T

8 You have a much greater choice of protocols for the B channel since the B channel is a neutral conduit for data of any type. You can use it to tran

9 In the diagram below, the two users are connected using two B channels in parallel. The ISDN is able to route these B channels independently, beca