Table 6.13 – Public Telephone Volume Controls
Current Guidelines:  
4.1.3  Accessible Buildings: New Construction.  Accessible buildings and facilities shall meet the following minimum requirements: . . . 

(17)  Public Telephones. . . .

(b)  All telephones required to be accessible and complying with 4.31.2 through 4.32.8 shall be equipped with a volume control.  In addition, 25 percent, but never less than one, of all other public telephones provided shall be equipped with a volume control . . . .
 
4.30.7 Symbols of Accessibility. . . .

(2)  Volume Control Telephones.  Telephones required to have a volume control by 4.1.3 (17) (b) shall be identified by a sign containing a depiction of a telephone handset with radiating sound waves. 

4.31.5  Hearing Aid Compatible and Volume Control Telephones Required by 4.1. . . .

(2)  Volume controls capable of a minimum of 12 dba and a maximum of 18 dba above normal, shall be provided in accordance with 4.1.3.  If an automatic reset is provided then 18 dba may be exceeded.  

Final Revised Guidelines:  
217.3  Volume Controls.  All public telephones shall have volume controls complying with 704.3.

704.3  Volume Control Telephones.  Public telephones required to have volume controls shall be equipped with a receive volume control that provides a gain adjustable up to 20 dB minimum.  For incremental volume control, provide at least one intermediate step of 12 dB of gain minimum.  An automatic reset shall be provided.

Model Codes & Standards
IBC 2000:  Section E1106.3 of Appendix E has a similar requirement for public telephones with volume controls. 

IBC 2003:  Section E106.3 of Appendix E has an equivalent requirement for public telephones with volume controls. 

ICC/ANSI A117.1-1998:  Section 704.3 has an equivalent requirement for level of volume control.