USRobotics USR9110 Guide D'installation page 6

Step One: Connect Microfilter(s) (if included or required by your ISP)
A microfilter removes interference between voice and DSL signals. Your ISP will determine
if a microfilter is necessary. If a microfilter was not included with the Wireless 54Mbps
ADSL Router, ask your ISP if you need to purchase one or more.
To install a microfilter, plug each device (phone, fax machine, or other telephony device)
into the microfilter and then plug the microfilter into the telephone wall jack. Do not
install a microfilter on the cable that will connect your Wireless 54Mbps ADSL Router to
the telephone jack unless your microfilter has a connection for both the router and the
phone.
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