AT&T MERLIN LEGEND System Reference Manual page 36

System Overview
Data Stations A data station is any location that includes a data terminal (such as a personal
computer, printer, or fax machine) connected to the system via a modem or a
data module, such as an ISDN 7500B Data Moduie. The modem or data module
transmits information to and from the data terminal and, in many cases, provides
dialing and answering capability. During data communications, a modem or
data module functions similarly to the way a telephone functions during voice
communications-it makes, maintains, and ends a call.
The two types of data stations that can be connected to the system are analog
and digital. Both types can include a telephone for users who require
simultaneous voice and data capability.
Analog Data Station uses a modem to convert the digital signals from the
data terminal to analog signals, which are then transmitted as continuous
electrical waves in the voice frequency band. The modem makes, receives,
or maintains the data call; it transmits or receives analog data over the
regular telephone company network or from another data station inside the
system.
An analog data station can be connected directly to the control unit via a
jack on a 012 or a 008 OPT module. If the data station includes an analog
multiline telephone, the modem is connected to the telephone by using a
General Purpose Adapter. If the data station includes an MLX telephone, the
modem is connected by using a Multi-Function Module (MFM).
Digital Data Station uses a data module such as an ISDN 7500B Data
Module to transmit digital signals as a sequences of separate electrical
pulses. The data module serves as an interface between the data terminal
and the system's control unit and is used to make, receive, or maintain the
data calls. The data module transmits and receives data over telephone
company digital facilities, such as Integrated Services Digital Network
Primary Rate interface (ISDN-PRI), or from another digital data station inside
the system.
A digital data station connects through a 2- or 4-pair cable to a jack on a 008
MLX module in the control unit.
Data Station Uses
Both analog and digital data stations can be configured for data
communications with
an individual data terminal (computer, printer, or fax machine)
a mainframe computer
a workstation on a LAN (a network of interconnected computers or terminals)
Data calls can be made between data stations. Calls between analog data
stations or calls between digital data stations are possible without additional
equipment. CalIs between an analog data station and a digital data station are
possible only if the system includes a conversion resource called a modem
pool.
Capabilities 1-9