Goto Section: 68.316 | 68.318 | Table of Contents

FCC 68.317
Revised as of December 10, 2018
Goto Year:2018 | 2020
  § 68.317   Hearing aid compatibility volume control: technical standards.

   (a)(1) A telephone manufactured in the United States or imported for
   use in the United States prior to February 28, 2020, complies with the
   volume control requirements of this section if it complies with:

   (i) The applicable provisions of paragraphs (b) through (g) of this
   section; or

   (ii) Paragraph (h) of this section.

   (2) A telephone manufactured in the United States or imported for use
   in the United States on or after February 28, 2020, complies with the
   volume control requirements of this section if it complies with
   paragraph (h) of this section.

   (b) An analog telephone complies with the Commission's volume control
   requirements if the telephone is equipped with a receive volume control
   that provides, through the receiver in the handset or headset of the
   telephone, 12 dB of gain minimum and up to 18 dB of gain maximum, when
   measured in terms of Receive Objective Loudness Rating (ROLR), as
   defined in paragraph 4.1.2 of ANSI/EIA-470-A-1987 (Telephone
   Instruments With Loop Signaling) . The 12 dB of gain minimum must be
   achieved without significant clipping of the test signal. The telephone
   also shall comply with the upper and lower limits for ROLR given in
   table 4.4 of ANSI/EIA-470-A-1987 when the receive volume control is set
   to its normal unamplified level.

   Note 1 to paragraph (b): Paragraph 4.1.2 of ANSI/EIA-470-A-1987
   identifies several characteristics related to the receive response of a
   telephone. It is only the normal unamplified ROLR level and the change
   in ROLR as a function of the volume control setting that are relevant
   to the specification of volume control as required by this section.

   (c) The ROLR of an analog telephone shall be determined over the
   frequency range from 300 to 3300 HZ for short, average, and long loop
   conditions represented by 0, 2.7, and 4.6 km of 26 AWG nonloaded cable,
   respectively. The specified length of cable will be simulated by a
   complex impedance. (See Figure A.) The input level to the cable
   simulator shall be −10 dB with respect to 1 V open circuit from a 900
   ohm source.

   (d) A digital telephone complies with the Commission's volume control
   requirements if the telephone is equipped with a receive volume control
   that provides, through the receiver of the handset or headset of the
   telephone, 12 dB of gain minimum and up to 18 dB of gain maximum, when
   measured in terms of Receive Objective Loudness Rating (ROLR), as
   defined in paragraph 4.3.2 of ANSI/EIA/TIA-579-1991
   (Acoustic-To-Digital and Digital-To-Acoustic Transmission Requirements
   for ISDN Terminals). The 12 dB of gain minimum must be achieved without
   significant clipping of the test signal. The telephone also shall
   comply with the limits on the range for ROLR given in paragraph 4.3.2.2
   of ANSI/EIA/TIA-579-1991 when the receive volume control is set to its
   normal unamplified level.

   (e) The ROLR of a digital telephone shall be determined over the
   frequency range from 300 to 3300 Hz using the method described in
   paragraph 4.3.2.1 of ANSI/EIA/TIA-579-1991. No variation in loop
   conditions is required for this measurement since the receive level of
   a digital telephone is independent of loop length.

   (f) The ROLR for either an analog or digital telephone shall first be
   determined with the receive volume control at its normal unamplified
   level. The minimum volume control setting shall be used for this
   measurement unless the manufacturer identifies a different setting for
   the nominal volume level. The ROLR shall then be determined with the
   receive volume control at its maximum volume setting. Since ROLR is a
   loudness rating value expressed in dB of loss, more positive values of
   ROLR represent lower receive levels. Therefore, the ROLR value
   determined for the maximum volume control setting should be subtracted
   from that determined for the nominal volume control setting to
   determine compliance with the gain requirement.

   (g) The 18 dB of receive gain may be exceeded provided that the
   amplified receive capability automatically resets to nominal gain when
   the telephone is caused to pass through a proper on-hook transition in
   order to minimize the likelihood of damage to individuals with normal
   hearing.

   (h) A telephone complies with the Commission's volume control
   requirements if it is equipped with a receive volume control that
   provides, through the receiver in the handset of the telephone, at the
   loudest volume setting, a conversational gain greater than or equal to
   18 dB and less than or equal to 24 dB Conversational Gain when measured
   as described in ANSI/TIA-4965-2012 (Telecommunications—Telephone
   Terminal Equipment—Receive Volume Control Requirements for Digital and
   Analog Wireline Telephones). A minimum of 18 dB Conversational Gain
   must be achieved without significant clipping of the speech signal used
   for testing. The maximum 24 dB Conversational Gain may be exceeded if
   the amplified receive capability automatically resets to a level of not
   more than 24 dB Conversational Gain when the telephone is caused to
   pass through a proper on-hook transition, in order to minimize the
   likelihood of damage to individuals with normal hearing.

   (i) The standards required in this section are incorporated by
   reference with the approval of the Director of the Federal Register
   under 5 U.S.C. 552(a) and 1 CFR part 51. All approved material is
   available for inspection at the Federal Communications Commission
   (FCC), 445 12th St. SW, Reference Information Center, Room CY-A257,
   Washington, DC 20554, (202) 418-0270, and is available from the source
   indicated below. They are also available for inspection at the National
   Archives and Records Administration (NARA). For information on the
   availability of this material at NARA, call 202-741-6030 or go to
   http://www.archives.gov/federal-register/cfr/ibr-locations.html.

   (1) The following standards are available from the Telecommunications
   Industry Association (TIA), 1320 North Courthouse Road, Suite 200,
   Arlington, VA 22201, (877) 413-5184, email to
   smontgomery@tiaonline.org, and
   http://www.tiaonline.org/standards/catalog.

   (i) Paragraph 4.1.2 (including table 4.4) of American National
   Standards Institute (ANSI) Standard ANSI/EIA-470-A-1987, Telephone
   Instruments with Loop Signaling, July 1987.

   (ii) Paragraph 4.3.2 of ANSI/EIA/TIA-579-1991, Acoustic-to-Digital and
   Digital-to-Acoustic Transmission Requirements for ISDN Terminals,
   February 1991.

   (iii) ANSI/TIA-4965-2012, Telecommunications; Telephone Terminal
   Equipment; Receive Volume Control Requirements for Digital and Analog
   Wireline Handset Terminals, approved October 19, 2012.

   (2) [Reserved]

   [ 61 FR 42187 , Aug. 14, 1996, as amended at  64 FR 60726 , Nov. 8, 1999;
    67 FR 13229 , Mar. 21, 2002;  69 FR 18803 , Apr. 9, 2004;  83 FR 8632 , Feb.
   28, 2018]

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Goto Section: 68.316 | 68.318

Goto Year: 2018 | 2020
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