ISDN - Integrated Service Digital Network
An ISDN user can set up two simultaneous independent Telecom
calls on the
existing pair of telephone wires. The two simultaneous calls can be of any
type - speech, data, image or video.
existing pair of telephone wires. The two simultaneous calls can be of any
type - speech, data, image or video.
Using an ISDN line the data transfer rate with another ISDN
line on dial-up basis
is a fantastic 64 Kbps ! It can go upto 128 Kbps !!
is a fantastic 64 Kbps ! It can go upto 128 Kbps !!
Features of ISDN
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Universality : | Various facilities in the same interface. |
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Portability : | Shifting of terminal possible during call. |
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Integration of Services : | Speech, facsimile or data can be transmitted through the same channels. |
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Flexibility of Services& : | Disconnecting / connecting the services needed by the subscriber is possible. |
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Broad band : | ISDN can provide broadband connections (more than 64 kbps) also. |
| The interface between the ISDN subscriber and the network is called User Network Interface. There are two types of User Network Interface :- | ||
| 1. | ISDN - Basic Rate Access Service |
| 2. | ISDN - Primary Rate Access Service |
ISDN - Basic Rate Access Service With an ISDN line you can do video-conferencing with another ISDN subscriber on dial up basis. Two types of Video conferencing are being offered.
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a) an ISDN Phone Set, b) a PC through an ISDN data card or digital Modem, c) Video Conferencing equipment - for conference over long distances. d) Digital-G4 FAX - a much faster and better quality of FAX sending with another G4 FAX. How to connect an ordinary phone or FAX ? No problem. Connect to the NT1 through a Terminal Adapter ( TA ). | ||||||||||||||
| BRIEF LOOKS ISDN Feature Phone :- It looks like a feature phone with hands-free operation, memory dialling, LCD display etc. It can display the dialed No. calling party No. for an i/c call, & short text message. It can store the calling No. in case of �no reply� for later retrieval (log-in facility). It is also used for programming of MSN, CF etc. ( discussed later ). While signaling a �Call Waiting� it can display the waiting caller�s Phone No. also. It enables use of many ISDN facilities using existing Phones, Fax machines, Modem etc. The TA may have two types of connectors. Analog connector :- Connect ordinary phones, Modems, FAX, Answering machine, Cordless Phones etc. Data Port :- Any serial port of the PC can be connected to this port. Data transfer using standard software packages like TELIX, XTALK or PROCOMM is possible at 64 Kbps or faster speeds upto 128 kbps. Additional Modem is not required. ISDN PC card :- This card is fitted in a standard PC expansion slot. Data Transfer speed supported is 64 kbps & above. It consists of a PC with a VDU, a Video Camera and associated controller cards plus software. The system is connected to the Exch. via 1 to 3 ISDN lines (depending on the Model). The equipment establishes connection to a similar equipment on the other side by dialling. Video images of the conference participants & / or Video tape movies as well as conversations can be sent / received. Data transfer can also be done simultaneously. Both the transmitted & the received pictures can be viewed on two windows on the PC Monitor. On one ISDN line after the NT1 you can connect a maximum of 8 Telecom gadgets using RJ45 plug and sockets. The internal wiring in the subscriber premises is terminated on RJ45 sockets, all in parallel on a 8-wire S-bus. However, only two gadgets at a time may be used on one ISDN connection. Video conferencing will, of course, be only one at a time. �PHONE PLUS� facilities on an ISDN Line : ISDN also supports a whole new set of additional facilities boosting the versatility of usage. | |||||||||||||||
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Primary Rate ISDN Line
A primary rate (PRI) ISDN line is designed to provide ISDN facilities to corporate EPABX extensions or access to a Server computer / corporate Intranet.
A PRI ISDN line supports 30 B channels and depending on bandwidth requirements, for any one communication any combination of B channels - up to 30, can be used.
The bit transmission rate on a PRI ISDN link is 2 Mb/s with time slot structure same as that of a normal TDM / PCM link used for inter-exchange junctions. So, the link is supported either on copper cable with Digiplexers at both ends, or on all standard media used for inter-exchange links e.g. optical fibre, microwave, satellite etc.
The PRI ISDN line is terminated onto NT2 at the Customer�s premises.
( NT2 is to be provided by the customer )
Q 1 : Does ISDN connection require any special cable to be laid ?
Ans : No. ISDN line works on the same copper cable up to a distance of 5 Km (approx.) from the
Exchange/RSU. However, ISDN lines cannot be extended over longer distances as of now.
Q 2 : Will ISDN connection help in getting INTERNET Access ?
Ans : INTERNET consists of a world-wide network of Information Banks. An ISDN line can be used to
access the INTERNET and in that case the data transfer speed would be 64 kbps or more !
Q 3 : Do I get dial tone by connecting an ordinary phone set on an ISDN line ?
Ans : No. You need an NT1 to be connected first on the ISDN line cable pair. To hear dial tone, with the
NT1 either you will have to connect an ISDN Phone or, a Terminal Adapter and then through the
TA an ordinary phone set.
Q 4 : Will I get any electric shock by touching an ISDN line cable pair ?
Ans : An ISDN line cable pair carries 100 V DC across the leads. So, you may feel a mild shock which
is however not at all fatal to any human being.
Q 5 : Must the NT1 be kept always powered on ?Ans : Normally Yes. However, if there is no power connected to the NT1, you can still make a voice call
from your ISDN feature phone. But you will not be able to receive calls if the NT1 is powered off.
Q 6 : How an ISDN communication is disconnected ?Ans : Same way as for an ordinary phone call. However, ISDN communication can be released by
either party in communication.
Q 7 : From an ISDN Line can I contact a non-ISDN line ?
Ans : You can always make a voice call. But using an ISDN data card you will be able to engage in data communication only with another PC equipped with another ISDN data card. Video
conferencing with a non-ISDN line is, of course, out of question.
Q 8 : Will calls made from different gadgets on the ISDN line be billed separately?
Ans : NO. Since you are, after all, using only one ISDN connection, all your meter readings will be
added up and billed together.
Q 9 : How I will know I have been given MSN ?
Ans : You will notice that you are able to receive calls on your ISDN feature phone but can�t make any
outgoing call. Using the ISDN feature phone you will have to program your MSN 1st. Then you will
be able to make outgoing calls.
Q 10 : Shall I get Dynamic Locking Facility on my ISDN line?
Ans : YES, only on ISDN lines from EWSD exchanges / RSUs. However, as such tampering with an
ISDN line is difficult as the full set of Customer Premises Eqpt. Would be required ; plus one
would need to know the MSN programmed by the actual user. So, on the whole, security is high
with ISDN lines.
Q 11 : What are the informations carried by ISDN channels?
1. User information
2. Control information
3. Network information to subscribers
Q 12 : What is bearer service of ISDN ?
Ans : It is the means to convey information (speech, data and video ect.) between
users in real time and without alteration of the content of the message. This
includes speech service with 64kbps, 8khz circuit mode, 64kbps Audio data
analogous to normal PSTN service.
Ans : It is the means to convey information (speech, data and video ect.) between
users in real time and without alteration of the content of the message. This
includes speech service with 64kbps, 8khz circuit mode, 64kbps Audio data
analogous to normal PSTN service.
Q 13 : What are the supplementary services one can have using
ISDN?
Ans : Following are the supplementary services one can have using ISDN.
1. Direct dialling in services
2. Multiple subscribers numbers
3. Calling line Identification
4. Call Forwarding
5. Call Waiting
6. Call Transfer
7. Line Hunting
8. Conferance Call
9. Closed User Group
10. Advice of Charge
11. User to User Signalling Services.
Ans : Following are the supplementary services one can have using ISDN.
1. Direct dialling in services
2. Multiple subscribers numbers
3. Calling line Identification
4. Call Forwarding
5. Call Waiting
6. Call Transfer
7. Line Hunting
8. Conferance Call
9. Closed User Group
10. Advice of Charge
11. User to User Signalling Services.
Q 14 : What are the different access configuration of
ISDN?
Ans :
Point to point configuration.
|<------100 meter to 200 meter-------->|
Ans :
Point to point configuration.
|<------100 meter to 200 meter-------->|
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