67• Avoid using headphones after exposure to extremely loud noises, suchas rock concerts, that might cause temporary hearing loss. Temporaryhearing loss might cause unsafe volumes to sound normal.• Do not listen at any volume that causes you discomfort. If youexperience ringing in your ears, hear muffled speech or experienceany temporary hearing difficulty after listening to your portable audiodevice, discontinue use and consult your doctor.You can obtain additional information on this subject from thefollowing sources:American Academy of Audiology11730 Plaza American Drive, Suite 300Reston, VA 20190Voice: (800) 222-2336Email: info@audiology.orgInternet: www.audiology.orgNational Institute on Deafness and Other CommunicationDisordersNational Institutes of Health31 Center Drive, MSC 2320Bethesda, MD 20892-2320Voice: (301) 496-7243Email: nidcdinfo@nih.govInternet: http://www.cdc.gov/niosh/topics/noise/default.htmlNational Institute for Occupational Safety and HealthHubert H. Humphrey Bldg.200 Independence Ave., SWWashington, DC 20201Voice: 1-800-35-NIOSH (1-800-356-4647)Internet: http://www.cdc.gov/niosh/topics/noise/default.htmlOperating EnvironmentRemember to follow any special regulations in force in any areaand always switch your phone off whenever it is forbidden to useit, or when it may cause interference or danger. When connectingthe phone or any accessory to another device, read its user'sguide for detailed safety instructions. Do not connectincompatible products.As with other mobile radio transmitting equipment, users areadvised that for the satisfactory operation of the equipment andfor the safety of personnel, it is recommended that theequipment should only be used in the normal operating position(held to your ear with the antenna pointing over your shoulder ifyou are using an external antenna).