Dial-up - ISDN FAQ
Our 0845 and 0808 dial-up products were withdrawn from service in January 2015. To find out more about this, or if you have any questions please see our Dial-up closure FAQ.
- What is ISDN?
- What benefits does ISDN offer over normal dialup access?
- What do I need to access the Internet using ISDN?
- How do I order ISDN?
- Can I get broadband later after moving to ISDN?
- Does PlusNet support Connecting at 128k using channel bonding?
- Can I use channel-bonding using my fixed cost Anytime account?
- Is there anything I can do to make my use of channel bonding as efficient as possible?
ISDN stands for Integrated Services Digital Network. A standard for providing enhanced telephone and data transfer services based on digital technology. With ISDN, it is possible to send both voice and data signals over the same phone line at the same time.
The most common form of ISDN is ISDN2, also called BRI (Basic Rate ISDN). It uses three separate channels for communication, two 'B' Bearer channels that allow for either voice or data transfer, as well as a small 'D' data channel, used for control. Each of the 'B' channels can carry data at rates of up to 64,000 kbps. Compare that with normal telephone dial-up service that can transfer data at about 50,000 kbps.
Although broadband now offers much faster connection speeds, if broadband services are not available, ISDN provides a worthwhile alternative to regular dial-up access.[Top]
ISDN comes with two separate communication channels, allowing you to access the Internet with one channel, while using the telephone on the other. Alternatively, you can bond both channels together and access the Internet at 128,000 kbps, which is approximately three times faster than by regular dialup. (Although we say that the maximum connection speed on an analogue phone line is 56,000 kbps, this is strictly a theoretical top speed which would certainly never be reached in practice)
Another benefit of ISDN is that it takes only 1 to 3 seconds to connect, compared to up to thirty seconds on a regular dialup service.[Top]
In order to use ISDN, you will need:
- An ISDN telephone service. It's common to have an existing phone service converted to ISDN rather than having an additional service fitted.
- An ISDN Terminal Adapter or Router (which connects your PC or Router to the ISDN service)
- A computer that has been setup to access the Internet.
You should contact your telephone provider to inquire about the availability of ISDN.[Top]
Yes you can, but it requires the ISDN service to be reverted back to an analogue phone line as part of the broadband setup process.
Please note that reverting to an analogue setup means you can no longer have multiple phone numbers on one line. You will need to choose which telephone number to keep.[Top]
Yes, with PlusNet it is possible to connect both ISDN channels to the Internet at the same time and treat them as a single double-speed connection. This feature is not activated by default, you can learn how to set it up on our [LINK:/support/dial-up/info/channel_bonding.shtml]guide to channel bonding on ISDN.[Top]
Yes, providing you have the Business Anytime Premier+ account. You should be aware that when using channel-bonding you take up two separate connections so double the rate at which you use your guaranteed hours.[Top]
Yes, it is possible to configure channel bonding so that the second channel only connects when needed. You can learn how to activate this feature in our guide to ISDN Bandwidth On Demand.[Top]