Some adding features that are not available in classic telephone system are given here with access to packed switched network. Designed while provisioning digital transmission over voice, data and image transmission over telephone lines. ISDN service ability is to deliver: at minimum two simultaneous connections; voice, video or fax over a single line. If you’re thinking of moving from analogue telephone connection to ISDN, you should require an ISDN card in place of a modem. An ISDN connection can be established in seconds for the equipment that you connect to your ISDN line must be digital.

Connectivity:

The ISDN subscriber can have their full connectivity to other analogue telephone subscriber.
Integrated Service Digital Network (ISDN) resolves some of the problems associated with dial-up Net Access.
Following Connections are available like:

> Dial-up connection
> Cable TV Internet connection
> Satellite internet connection
> Wireless connection