The following companies offer accessible cell phone solutions for people who are deaf or hard of hearing. If you are looking for amplifiers, a TTY that can be used with a cell phone, a hearing aid compatible headset for use with cell phones, Bluetooth technology, and hearing aid compatible cell phones, see the links provided below.
When researching cellular phones, ask the wireless service provider about the opportunity to test the phone before you buy. If you are seeking a phone that will couple with a hearing aid's microphone, look for phones that have a rating of M3 or M4. A higher "M" rating indicates that the phone will be less likely to interfere with a hearing aid. If you are seeking a phone that will couple with a hearing aid's telecoil, look for phones that have a rating of T3 or T4. A higher "T" rating means the phone is less likely to interfere with the hearing aid when in the telecoil mode. This information comes from CTIA - The Wireless Association (www.accesswireless.org).
For information regarding Federal Communications Commission (FCC) rulings related to cellular telephones go to: http://www.fcc.gov/cgb/consumerfacts/hac.html