Telephone VoIP Adapter
A Telephone VoIP Adapter (or TVA) is a device that allows traditional digital PBX (Private branch exchange) telephone handsets, e.g., Nortel Meridian, & BCM or Siemens Optiset/Optpoint, to be connected to a VoIP network, using, for example, SIP (Session initiation protocol).
Comparison can be made with an ATA (Analog Telephone Adapter), which allows analog phones to be connected to VoIP networks. A TVA can also be called a Digital Telephone Adapter, as it allows digital phones to connect to a VoIP network.
A Centrex TVA VoIP enables centrex phones, such as Nortel P-Phones, and analog-based Centrex phones like BT Featureline.
Some telecom manufacturers have produced hybrid exchanges with TVA-like elements. So they support IP phones and also have units or cards that allow connection of the traditional digital phones. For instance Avaya IP Office release 7.0 supports expansion modules for Avaya's digital phones, or alternatively "heritage" Nortel Norstar/BCM phones.
Whether a standalone TVA (such as Citel's Portico TVA) or a hybrid PBX is deployed, the intention is to preserve investment in an installed base of telephone handsets, and remove the need to install ethernet infrastructure.[1][2][3]