TIA-912

Description / Abstract: This standard establishes transmission requirements for Voice Gateways (VGs) that interface with various elements of public and private telecommunications networks.For the purposes of this standard, a VG is considered to be a device that performs voice routing functions between:

• Telephones;
• Public and private analog and digital networks;
• Packet-based networks.¹

VGs include, but are not limited to:

• Packet-based Enterprise equipment that is functionally equivalent to a TDM-based PBX;
• Residential Gateways;
• Voice-over-ADSL Integrated Access Devices (IADs);
• Voice-over-Cable Multimedia Terminal Adaptors (MTAs).

The requirements contained in this standard are based on current understanding of required performance and on the capabilities of present technology. As technology evolves, or as performance needs change, these requirements may become subject to change.

PURPOSE

The transmission requirements contained in this standard are based on an industry-developed fixed loss and level plan. The requirements were developed with the objective of maintaining or improving the quality of service for connections within existing and evolving communication networks. Compliance with these requirements should assure acceptable service when VGs interface and connect with the various elements of public and private telecommunications networks.

This standard is intended to be coordinated with the public network loss plan according to the principles of ITU-T Recommendation G.101 and ANSI/ATIS-0100508.2003.

Additional voice quality-of-service issues such as the impact of transmission delay, speech compression and packet loss are addressed in TIA Telecommunications Systems Bulletins TSB-32-A and TSB-116-A.

¹ For historical reasons, the terms "IP" and "IP-based networks" are used extensively in this standard in a generic fashion, but the more generic terms "packet" and "packet-based networks" are now more appropriate. While it is not practical to replace every instance of "IP" with "packet" in this standard, it is the intent of this standard that "IP" and "packet" have the same generic meaning.