We have Plus.net FTTC running on the supplied Technicolor TG582n and BT Openreach Box. Speeds are normally fine at about 20-30 Mbits per sec and we've been using a Vodafone SureSignal for over a year with no issue. We recently added the EE SignalBox (Cisco USC3331) but instantly experienced problems with massive drops in speed when the SignalBox is turned on, to such extent that even basic webpages fail to load due to timeouts. Sometimes the speeds don't drop immediately after the EE box is turned on but sooner or later they always do. We have resorted to leaving the EE box off apart from once or twice a day to recieve text messages and voicemail but this is becoming a bit of a problem now. I have telephoned EE and they are saying it must be a problem with the router - any advice?