This ADSL Microfilter allows you to share broadband and telephone equipment on one socket. To ensure the quality of both the telephony and the ADSL, it is important that every piece of telephony equipment must be filtered including telephones, fax machines and even simple tone callers. This doesn\'t mean that every piece of equipment has to have a filter, only that every telephone socket that has telephony equipment attached to it should have a micro filter fitted first.