General DSL Performance Tips
Keep the length of your Cat 5 (Ethernet) cables under 300 feet. Exceeding this length may affect your DSL performance.
ANY device connected to your DSL enabled phone line (e.g. alarm systems, fax machines, game consoles, poor quality phones, etc) could cause interference on your line. To eliminate them as possible factors, you may want to consider temporarily removing them and test to see if there's any difference. Also, confirm that every device (besides the DSL modem) is plugged into a DSL filter if possible.
As a general rule of thumb, you should be capable of bursting up to 80% of your maximum speed. Overhead and other factors account for the 20% 'loss'. Please refer to this web page for additional information.
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