Telecommunication II 1 ISDN What is ISDN What

Telecommunication II 1

ISDN - What is ISDN? What is an ISDN telephone? What is an ISDN line? Did U ever use ISDN connection? How to get an ISDN connection? Which equipment is required? How much it costs? 2

History of ISDN § Analog Telephone • The early phone network consisted of a pure analog system that connected telephone users directly by an interconnection of wires. This system was very inefficient, very prone to breakdown and noise, and did not lend itself easily to long-distance connections 3

Old System - Using modem over a POTS (plain old telephone system) to connect to Internet through ISP: § The home dialup modem converts digital signal from computer to analog signal. § A modem in the ISP converts the signal back to digital form for input to ISP router. § Data transmission is limited to 56 kbps.

Analog and Digital Services

Integrated Digital Network

Integrated Services Digital Network

ISDN - ISDN Network Connection 8

ISDN - ISDN reference points/ Interfaces 9

ISDN - Integrated Services Digital Network - Introduction - ISDN brings the digital network to the individual user - Three separate channels at the same time, through the same line - Two of these channels (the B channels) carry user "conversations" from a telephone, a computer, a fax or almost any other device. The third channel (the D channel) carries call set-up information for the network, but can also carry user data 10 transmissions

ISDN - All information is transmitted in digital form from end to end - With the help of some hardware and software updating, modern digital telephone exchanges are able to provide ISDN service - The ordinary two-wire subscriber loop of the telephone network is upgraded to the basic rate access of ISDN by an NT on the subscriber premises and by a basic rate interface unit and ISDN software in the local exchange 11

ISDN - User data contain two independent 64 -Kbps circuit switched user channels, B channels, and a 16 -Kbps signaling channel, the D channel - Subscribers may use both B channels independently at the same time and dial them up independently, for example, using one of these channels for a telephone call and another for an Internet connection 12

ISDN - For Internet surfing B channels can be combined to provide a single 128 -Kbps data rate connection - ISDN provides a reliable 64/128 -Kbps connection end to end, which is much more than that available for subscribers using a voice-band modem over an ordinary analog telephone circuit - The advantages of ISDN over the analog telephone service are a higher data rate and the availability of two connections at the same time - ISDN connections sometimes at a lower cost than two conventional analog telephone connections 13

ISDN - Existing telephone can be connected to an analog port on the TA - Telephones connected to the TA can be used internally - To drive its convenience features, it wouldn't work in the event of power failure - If I connect both my fax machine and telephone to the TA, will they both ring when a call comes in, and is it possible for the TA to detect the type of call and route it to the appropriate device? - About additional telephone numbers 14

ISDN - An ISDN telephone - Integrated Services Digital Network (ISDN) - you may get one phone number per ISDN line or one phone number for each ISDN B-channel - Several TAs can be connected to a single ISDN line - An external TA or an ISDN card - Caller ID, Transfer, Conference, 30 -Number Speed Calling, Call Hold, Call Pickup, and Call Forwarding at no additional charge. Voice Mail is available at no cost, and ISDN provides a visual message-waiting light on each ISDN set 15

ISDN - Terminal Equipment - Any end-user equipment connected to an ISDN line through an NT device is called terminal equipment. There are two classes of terminal equipment in the ISDN world. They are ISDN-ready (or digital devices) and non-ISDN ready (or existing analog devices such as telephones, fax machines, and data modems). - TA, Terminal Adapter, allows analog voice and data devices to work through an ISDN connection. TA can be standalone equipment, but more often it is a port of an NT 1 or TE 1. - TE 1 refers to the ISDN device that supports the standard ISDN interface. It can be a digital phone, digital fax, or any other device that connects without an adapter. - TE 2 includes any device that is non-ISDN ready, such as all existing analog equipment. It cannot be connected to the ISDN line directly and requires a terminal adapter 16

ISDN - Network Termination Devices § Network termination devices serve as a demarcation point between telephone company and customer premises equipment. - NT 1 § The NT 1 is a two- to four-wire interface. It provides termination for the ISDN connection and supplies power to the ISDN line and non-powered ISDN devices - NT 2 § The NT 2 device is an intelligent device that supports higher-level functionality. It can perform switching and concentration functions. Examples of NT 2 are a 17 digital PBX, a terminal controller, and a LAN

ISDN (continued) - Two types of services provided through narrowband ISDN: 1. The basic rate interface (BRI): • is made of two B channels and 1 D channel, suitable for small businesses and residential. 2. The primary rate interface (PRI): • is made of either 23 B channels or 30 B channels and one D channel, is suitable for businesses with digital PBX or LAN.

ISDN (continued) The primary rate interface (PRI): • 23 B channels at 64 kbps each and one D channel at 64 kbps – Data rate=1. 544 Mbps » (used in USA, Canada, and Japan) • 30 B channels at 64 kbps each and one D channel at 64 kbps – Data rate=2. 048 Mbps » (used in Europe)

ISDN - ISDN services - BRI/PRI 20

Figure 15 -13 WCB/Mc. Graw-Hill BRI Interfaces The Mc. Graw-Hill Companies, Inc. , 1998

Figure 15 -17 WCB/Mc. Graw-Hill BRI Frame The Mc. Graw-Hill Companies, Inc. , 1998

Figure 15 -19 WCB/Mc. Graw-Hill PRI Interfaces The Mc. Graw-Hill Companies, Inc. , 1998

Figure 15 -20 WCB/Mc. Graw-Hill PRI Frame The Mc. Graw-Hill Companies, Inc. , 1998

ISDN - ISDN network components 25

ISDN - ISDN TA 26

ISDN - ISDN NT 1 27

Advantages of ISDN - Multiple Numbers § For single digital source, we can program upto 64 different numbers. - Multiple Services § ISDN is using packet switching technique, So at the same point of time we can utilize more than one service. - Out-of-Band Signal § The Digital packet having the information like who is calling, what type of call is it (data/voice), and what number was dialed. Using this information we can do the intelligent call handling. 28