HTC EVO Shift 4G Basic Manual page 146

Please power off the Bluetooth function while using
hearing aid devices with your PG06100.
Hearing devices may
also be rated. Your
hearing device
manufacturer or
hearing health
professional may help
you find this rating.
Higher ratings mean
that the hearing device
is relatively immune to
interference noise.
The hearing aid and wireless phone rating values are
then added together. A sum of 5 is considered
acceptable for normal use. A sum of 6 is considered
for better use. A sum of 8 is considered for best use. In
the above example, if a hearing aid meets the M2 level
rating and the wireless phone meets the M3 level
rating, the sum of the two values equal M5. This should
provide the hearing aid user with "normal usage" while
using their hearing aid with the particular wireless
phone. "Normal usage" in this context is defined as a
signal quality that is acceptable for normal operation.
140 3B. Regulatory Notices
This methodology applies equally for T ratings. The M
mark is intended to be synonymous with the U mark.
The T mark is intended to be synonymous with the UT
mark. The M and T marks are recommended by the
Alliance for Telecommunications Industries Solutions
(ATIS). The U and UT marks are referenced in Section
20. 1 9 of the FCC Rules. The HAC rating and
measurement procedure are described in the
American National Standards Institute (ANSI) C63. 1 9
standard.

For information about hearing aids and digital
wireless phones
FCC Hearing Aid Compatibility and Volume
Control:
http://www.fcc.gov/cgb/dro/hearing.html
Gallaudet University, RERC:
https://fjallfoss.fcc.gov/oetcf/eas/reports/Generic-
Search.cfm