The POTS splitter may also be installed on the outside of the house adjacent to the telephone network interface device (NID).
(ADSL over ISDN)
A ISDN splitter separates ADSL signals from ISDN signals on your ISDN telephone line. The ISDN splitter works by running a separate ADSL line from the ISDN line, so that the ADSL router has a dedicated cable for data transmission. Figure