[. . . ] may be subject to interference from obstructions, such as walls, or other electronic devices. The headset complies with the Bluetooth Specification 2. 0 + EDR that supports the Headset Profile 1. 1 and Hands-Free Profile 1. 5. Check with the manufacturers of other devices to determine their compatibility with this device. There may be restrictions on using Bluetooth technology in some locations. [. . . ] The mobile device and the headset do not need to be in line of sight, but they should be within 10 meters (30 feet) of each other. Connections 3 Get started The headset contains the following parts shown on the title page: power key (1), charger connector (2), earpiece (3), microphone (4), earloop (5), volume key (6), indicator light (7), and answer/end key (8). Before using the headset, you must charge the battery and pair the headset with a compatible device. Parts of the headset are magnetic. Do not place credit cards or other magnetic storage media near the headset, because information stored on them may be erased. Warning: Use only chargers approved by Nokia for use with this particular enhancement. The use of any other types may invalidate any approval or warranty and may be dangerous. When you disconnect the power cord of any enhancement, grasp and pull the plug, not the cord. Charge the battery The headset has an internal, nonremovable, rechargeable battery. Do not attempt to remove the battery from the device, as you may damage the device. If Chargers Check the model number of any charger before using it with this headset. The headset is intended for use with the AC-3, AC-4, and DC-4 chargers. 4 charging does not start, disconnect the charger, plug it in again, and retry. To change the cover, pull the current cover starting from the top (13), and push the new cover into place. Call handling To make a call, use your mobile device in the normal way when the headset is connected to the device. If your device supports last number redialing with the headset, press the answer/end key twice while no call is in progress. If your device supports voice dialing with the headset, press and hold the answer/end key when no call in progress, and proceed as described in the user guide of your device. To switch the call between the headset and a compatible device, press and hold the answer/end key. Clear settings or reset To clear all the pairing settings from the headset, switch off the headset, and press and hold the power key and the answer/end key until the red and green indicator lights start to alternate. To reset the headset if it stops functioning, although it is charged, plug the headset into a charger, and press the power key and the answer/end key at the same time. Battery information Your device is powered by a rechargeable battery. The battery can be charged and discharged hundreds of times, but it will eventually wear out. Recharge your battery only with Nokia approved chargers designated for this device. Unplug the charger from the electrical plug and the device when not in use. Do not leave a fully charged battery connected to a charger, since overcharging may shorten its lifetime. If left unused, a fully charged battery will lose its charge over time. [. . . ] If left unused, a fully charged battery will lose its charge over time. Never use any charger that is damaged. 7 Leaving the device in hot or cold places, such as in a closed car in summer or winter conditions, will reduce the capacity and lifetime of the battery. Always try to keep the battery between 15°C and 25°C (59°F and 77°F). A device with a hot or cold battery may not work temporarily, even when the battery is fully charged. [. . . ]