CompTIA Network+

Answer: C - As the name implies, a splitter splits the signals coming into the phone into voice and data signals. It sends voice signals below 3.4 KHz to the telephone and the signals above 3.4 KHz to the modem.

Key Takeaway: A splitter is a device connected between the NID and the telephone/modem interface to divide voice and data signals on the telephone line. The human voice falls between 0 and 3.4 KHz, so the splitter sends transmissions below 3.4 KHz to the telephone and transmissions above 3.4 KHz to the ADSL modem. A malfunctioning splitter would normally give a high frequency static on the telephone in place of a dial tone.