|Line level signals are commonly
used for sending audio from one device to another. Patch cords usually
carry a line level signal. Line level is defined as any signal above 25
millivolts RMS. Professional devices at 0 dB VU meter output
+4 dbm or 1.228 volts RMS 9600 ohms impedance). Domestic or home entertainment
devices (CD players, cassette decks, etc.) and semi professional studio
devices will use a -10 dB signal in 10,000 ohms impedance which has considerable
less gain (.5 volts).
Devices designed for electric guitar
signals are designed to face an even higher impedance (100,000 ohms +)
and may output a wide array of line level values.