R interface defines the point between a non-ISDN device and a terminal adapter (TA) which provides translation to and from such a device.

When using cable operator VoIP, a combined customer premises equipment device known as an embedded multimedia terminal adapter (E-MTA) will often be used.

These clocks are usually quite accurate, but in some low-cost terminal adapters (a one or two-line gateway) the PCM clock can be surprisingly inaccurate.

In comparison, the more modern terminal adapters generally included a command line interface that allowed the user to select a host from a directory that appeared on their terminal.

In Mobile networks, the terminal adapter is used by the Terminal equipment to access the Mobile termination, using AT commands (see Hayes command set).

The T interface is a serial interface between a computing device and a terminal adapter, which is the digital equivalent of a modem.

However, these operators generally offer free hardware that also allows the use of POTS equipment, such as NTBAs with integrated terminal adapters.

Where an analog connection requires a modem, an ISDN connection requires a terminal adapter (TA).

With digital telephones, modems will be replaced by devices called terminal adapters that link computers to a digital telephone network.

The physical equipment is also known as a terminal adapter.