What is line sharing?

In a technological sense, ADSL service may be provided over the same 2-wire line as a standard telephone or ISDN public network connection. More...

This opens the commercial possibility of simltaneous telephone and ADSL over a single 2-wire telephone line (‘line sharing’) – but provided by two distinctly separate service providers. Typically this works as follows:

The old telephone company (ex-monopoly or ‘incumbent’ operator) provides the 2-wire line from the customer’s premises to his nearest telephone exchange building (typically within 3-5 km) and usually provides the basic telephone and/or ISDN service across this connection. Meanwhile, the ADSL service provider makes use of ‘line sharing’ of this line by providing his ADSL customer with a DSL splitter and/or modem. Meanwhile, the ADSL service provider also shares the use of the incumbent operator’s DSLAM. The onward connection from the DSLAM to the public Internet is then arranged by the ADSL service provider.

The ADSL service provider usually pays a monthly fee to the incumbent operator for ‘line sharing’. In addition, he may be required to pay a one-off installation fee, a one-off cancellation fee and service or fault repair charges.

Why should an incumbent operator provide line sharing? The answer is usually “because the national telecommunications regulator has forced him to do so – in an attempt to increase competition in provision of telecommunications services”.

Under line sharing, the customer will usually receive two separate monthly invoices:

4 One from the ‘incumbent’ operator for telephone line service (monthly subscription) and calls made, and

4 One from the ADSL service provider or ISP (Internet Service Provider) for monthly connection fee and data volume charges (or data flatrate).

The level of service you receive, and the overall performance of your Internet access line as an ADSL customer will depend not only upon how well the ADSL service provider’s Internet access network operates, but also upon the level of service of the incumbent operator in maintaining the DSLAM. In cases where the incumbent operator is only a grudging provider of the ‘line sharing’ capability, the ADSL service level may be adversely affected.