cossie,
Here's my understanding of your ADSL / Analog telephone setup:
1) You have a single POTS (plain old telephone service) line coming into your home with ADSL service running on this line.
2) You have an ADSL modem and broadband router to connect your PCs to the Internet
3) You have a Panasonic telephone/answering machine
4) You have a Brother MFC all-in-one fax, copier, printer from which you need to send/receive faxes from
5) You have other analog telephones in your house that you want dialtone on without messing up your DSL or any other devices
In general, when you have DSL running over your existing POTS line, you need to attach a filter to every analog device that's plugged into your telephone line. This includes fax machines, answering machines, analog modems and plain old telephones.
As for your plain old telephones, as long as they have a filter installed on their connections, this should not interfere with your DSL service.
So basically the DSL modem requires DIRECT access to your raw telephone line where the other devices need to connect to the raw line via a filter.
You can install individual filters for each analog device OR you can install a single filter at the site of connection which has filtered output (goes to all your analog devices) and unfiltered output (goes directly to your DSL modem).
Check out:
http://www.wisegeek.com/what-is-a-dsl-filter.htm
The other issue in your configuration would be to determine the answering order of your Panasonic telephone/answering machine and your Brother MFC fax/copier/printer. You said that your Panasonic telephone/answering machine is configured to pick up after 4-6 rings. What about your Brother fax machine? Do you need THIS device to automatically answer and accept incoming fax calls? If so, which device should pick up first? Knowing how you want these two devices to behave changes the order in which they're connected to your filtered telephone line as well as the configuration on each device.
- John