Some subscribers are disappointed when informed that although initial line checks were successful, ADSL2+ is unavailable at their address. This is often due to issues with either a "pair-gain" or RIM on the phone line, restricting the type of broadband service available. However, a pair-gain or RIM failure doesn’t necessarily mean you will be unable to connect a broadband connection as you can generally request to have them removed. Unfortunately you will not be able to receive ADSL2+ speeds when there is a pair-gain or RIM on the line.
Pair Gain
If your telephone infrastructure is connected to a pair-gain system you will not be able to run an ADSL2+ service. A pair-gain system refers to the technology used to run several phone services along the same length of copper line from the exchange. Telecommunications providers will often install pair-gains systems to reduce installation costs and cabling space when connecting multiple phone services.
Instead of installing a separate copper line into each premise, a pair gain system will use the same line that is then split and run into several houses. The resulting line is adequate for a phone service but cannot support a high speed broadband connection.
In most cases you can request for your internet service provider to attempt to remove the pair gain system. If you have applied for an ADSL2+ service and received a pair-gain notice, the internet service provider will usually offer to attempt to remove it and provide and ADSL service. The removal is successful in around 70% of cases and will allow an ADSL service to run on the line. Unfortunately, even with the pair gain removed, you will not be able to receive an ADSL2+ service as connection is restricted to ADSL speeds.
RIM
An RIM or Remote Integrated Multiplexer is often installed by Telstra to extend copper line to reach more areas. A RIM will allow a signal to travel further along the line and can also be used to split a copper line to several premises. There are a number of reasons why Telstra may install a RIM on your line including insufficient space for more cables, cable-laying difficulties or the overall expense of copper cabling.
If there is RIM infrastructure on your home phone line you will be unable to run a high-speed ADSL2+ broadband service. The fastest connection possible on a RIM service is an ADSL connection. Your internet service provider will suggest suitable connection once a RIM notification as been issued. If you have been notified of a pair gain or RIM on your phone line, you can search ADSL broadband plans here.