Difference Between DSL & ISDN

Digital Subscriber Line (DSL) and Integrated Services Digital Network (ISDN) are both copper phone line Internet connections limited in service by distance from a central office (CO), but the similarities end there. DSL is superior in nearly every relevant category.

Connectivity

In terms of connectivity, DSL is an always-on connection; ISDN works on a dial-up basis, meaning users must use a program to dial the connection and hang up the call to end it.

Speed

DSL download speeds can scale to as high as 8 Mbps; ISDN is limited to a maximum download speed of 384 Kbps, and more commonly 128 Kbps, which is only marginally faster than dial-up Internet.

Cost

ISDN is usually more expensive than DSL because it requires installation and DSL does not.

Equipment

DSL requires a special modem or router issued by a service provider that is set up by a subscriber; ISDN requires no such special modem, but instead requires a terminal adapter to be connected to a computer, usually by an expert.

Availability

It is more likely that ISDN will be more available than DSL. This is because it is essentially two or more telephone lines used in conjunction.

References

• CTI Networks: ISDN FAQ
• DSL Service Providers: DSL vs ISDN Connection
• Buy Telco: ISDN vs. DSL