Isolation Tests & Filtering
Isolation Test
If you are having problems with your Line you and you call your ISP about this, you will be asked by your ISP to conduct an Isolation Test.
http://whirlpool.net.au/wiki/?tag=Isolation_Test
basically it means you need to disconnect ALL the devices from the Telephone line and Outlets and then reconnect the Modem and then after succesfull connection you then start plugging in each device one at a time to see which outlet/ device is causing the problem
And they Might ask you about what Filters you have in Place.
Many Modems come with filters they are generlaly ok...
the Best type are either ACS [1] or C10 [2]
Filtering
You need to have every device Filtered.. Extra Handsets (base stations for cordless phones), Fax Machines, Dial up Modems and Dialer devices Like Alarms and Medic alert devices you can only have 3 devices filtered via inline filters any more than that, you will need a Central Filter installed for you.