Modem ADSL (Asymetric Digital Subscribe Line) which allows internet surfing and using analog phones simultaneously. It's easy, for ADSL is given a device called a splitter or divider line. Splitter positions are placed in front when the incoming phone line. This means you can not graft to the ADSL modem line with direct sound. Splitter useful tool to eliminate distractions when you're using ADSL modem. With Splitter both can run simultaneously, so users can answer and calling someone with a regular phone. On the other hand, users can still connect to the Internet via ADSL modem.