Detailed instructions for use are in the User's Guide.
[. . . ] Before charging the headphones batteries, always make sure that the batteries in the headphones are rechargeable types. Dispose of spent dry or rechargeable batteries conforming to local waste disposal rules. Never place the equipment near heat sources such as radiators or electric heaters or expose it to direct sunlight, excessive dust, humidity, rain, temperatures below freezing, or impacts. [. . . ] Never use alcohol, petroleum-based cleaners, or paint thinners to clean the headphones or transmitter. If you do not use your headphones system for an extended period of time (e. 2 V AAA size recharge-able batteries: NiMh, 600 mAh (K 406 AFC, K 520) or NiCd, 300 mAh (K 306 AFC) for powering the headphones (inside the headphones) If anything is missing, contact your AKG dealer immediately. Status LED: illuminates green to indicate power to the headphones is ON, and red to indicates the batteries inside the headphones are being charged. The POWER ON/CHARGE LED (11) on the transmitter will light red to indicate that the batteries in the headphones are being charged. If signal is present at the transmitter audio input, the POWER ON/CHARGE-LED (11) will light orange. You may leave the headphones on the transmitter for as long as you like without risking to overcharge the batteries. Before connecting the transmitter to your audio source, switch the audio source OFF. 5, plug the red RCA connector (right channel) on the supplied connecting cable into the red AUDIO IN R socket (7) and the white RCA connector (left channel) into the white AUDIO IN L socket (7) on the transmitter rear panel. After a few seconds, you should hear the signal in the headphones clearly and free of interference. If your first try fails, set the FREQ selector (9) on the transmitter to a different position and press AUTOTUNING (5) again. Has detected no signal for several minutes, headphones are on the transmitter, charging function is on. Has detected no signal for several minutes, headphones are not on the transmitter, charging function is off, OR . Operating switches on or connecting the transmitter to your audio source may cause clicks which at high volume settings may affect your hearing. Therefore, be sure to set the VOLUME control on the headphones to minimum before switching between different sources (tuner, turntable, CD player, etc. Listening over headphones at high volume levels, particularly over extended periods of time, may damage your hearing. your K 306/K 406/K 520 is a radio frequency device that conforms to the strict European standards. For physical reasons that have nothing to do with the quality of the product, extremely strong interference sources may affect reception. [. . . ] your K 306/K 406/K 520 is a radio frequency device that conforms to the strict European standards. For physical reasons that have nothing to do with the quality of the product, extremely strong interference sources may affect reception. In order to maintain interference-free listening pleasure, do not operate your K 306/K 406/K 520 in the close vicinity of radio equipment, cellular telephones, or directly above TV or computer monitor picture tubes (see fig. [. . . ]