This standard establishes performance and technical criteria for interfacing the analog telephone port of a terminal adapter with analog telephony equipment. It defines the electrical and telephony aspects (e.g., DTMF receiver and call progress signal generation) of the loop start analog telephone ports of terminal adapters. However, it is not intended to be a complete equipment specification. Other interfaces (e.g., LAN interface) for connection to IP or packet-based networks are outside the scope of this standard.

In this standard, the terminal adapter is considered customer premises equipment for the connection of on-premises analog telephony equipment via in-house wiring. Off-premises connection of analog telephony equipment is not covered in this standard.

The requirements in this standard ensure compatibility of the analog telephone port with the analog telephony equipment complying with the parameters specified in ANSI/TIA-470.110-D, ANSI/TIA- 470.112, ANSI/TIA-470.210-E, ANSI/TIA-470.220-D, ANSI/TIA-470.230-C, and ANSI/TIA-777-A.

The requirements in this standard may include parameters beyond the limits specified in other standards for analog telephony equipment. Specifying parameters beyond those of other telephone standards will increase the ATA compatibility with existing analog telephone devices currently in use.

This standard does not define the stimulus required on the packet-based interface to test the requirements of the analog telephone port.