AT&T MERLIN LEGEND Release 3.1 System Manager's Manual page 71

Data Communications Capabilities
For high-speed data communications over Integrated Services Digital Network
Basic Rate Interface (NI-1 BRI, Release 4.0 and later) or Digital Signal 1 (DS1)
Primary Rate Interface (PRI) or T1 Switched 56 (Release 4.0 and later) facilities,
you can attach an ExpressRoute 1000 ISDN Terminal Adapter or another ISDN
(Integrated Digital Services Network) terminal adapter to an MLX telephone.
Group videoconferencing may require an ExpressRoute 1000, or an ISDN
terminal adapter compatible with them, which may be provided with the
videoconferencing application. A modem or ISDN terminal adapter can operate
(with its data terminal, of course) from its own extension, with no telephone at
the extension.
Desktop videoconferencing, data transfer, and screen-sharing applications
work with Release 4.0 and later systems.They use any combination of PRI, NI-1
BRI, and T1 Switched 56 data lines/trunks. Such systems can stand alone, and
some may also have an MLX telephone attached. Desktop videoconferencing
systems can use one MLX B-channel or two (for acceptable video quality). If the
system uses both MLX B-channels, you cannot use the phone connected to the
same MLX port as the videoconferencing application while the desktop
videoconferencing system is making or receiving calls. The use of two
B-channels is called 2B data .
2–30
About the System