Some clarification does seem needed here. stev, is your broadband Internet access provided by your cable company or it is a telephone-line based connection? DSL is a telephone-line based connection. So, DSL or cable, which is it?
The filters mentioned in this discussion apply to DSL, not to cable. If you have DSL, your ISP would normally have sent you some DSL filters along with the modem.
Who is your ISP?