ISDN or Integrated Services Digital Network is a circuit-switched telephone network system that transmits both data and voice over a digital line. You can also think of it as a set of communication standards to transmit data, voice, and signalling.

These digital lines could be copper lines. It was designed to move outdated landline technology to digital.

ISDN connections have a reputation for providing better speeds and higher quality than traditional connections. Faster speeds and better connections allow data transmissions to travel more reliably.

It’s easy enough to define ISDN, but do you know how it works?

Most people use ISDN for high-speed internet when options like DSL or cable modem connections are not available. Setting up ISDN is something you’ll want to work on with your Internet Service Provider (ISP). A lot of the steps can easily be done from your home.
Your ISDN will be plugged in through a traditional POTS (Plain Old Telephone Service) line that can access both phone numbers at once. You’ll have to make sure you have a working POTS line and assigned phone numbers to begin. After that, you can follow the steps below to get your voice
and data communications up and running.

ISDN SETUP
Setting up an ISDN connection involves using a serial port and plugging in the telephone company line.
The process of setting up ISDN involves:
Loading the modem driver disk and programming the modem
Pointing the modem toward the right phone numbers
Setting your connection speeds for each line
Directing your modem to dial your ISP (Internet Service Provider) this phone number should be provided by your ISP
If necessary, set your modem for BONDING (the ability to access higher speeds by allowing your modem to dial both phone numbers at once)

What are the advantages of ISDN?
So why do people use ISDN?
It first started as an alternative to your dial-up connection that provided higher internet speeds. To access the internet with ISDN, users had to connect through a digital modem. People still use ISDN for internet access in areas where broadband internet isn’t an option. For the most part, ISDN for internet access is being phased out.
There have been many attempts to improve the ISDN service. Broadband ISDN, also known as B-ISDN, transmitted data over fiber optic cable. Another attempt was ISDN BRI which attempted to improve voice services. 

Some of the reasons people choose ISDN are:

• It offers multiple digital services that operate through the same copper wire
• Digital signals broadcast through telephone lines.
• ISDN provides a higher data transfer rate.
• Can connect devices and allow them to operate over a single line. This includes credit card readers, fax machines, and other manifold devices.
• It is up and running faster than other modems.

Experiments List
01.     Topology: Star, Ring, Bus
02.     Hub : 5 Port
03.     ADSL connection with router: 4 port
04.     Major experiment work with this kit
05.     Input volts= 230 VAC
06.      Input frequency= 50 Hertz
07.     WLAN access
08.     Access point creation
09.     Wireless network file sharing
10.     File sharing over the network