Data Capabilities - AT&T MERLIN LEGEND System Reference Manual

System Overview
Behind Switch Mode
Lines/Trunks by Mode

Data Capabilities

For more information on data
. .
communication hardware requirements,
feature descriptions, planning,
programming, and using data
communications equipment, see the
Data Guide.
1-8 Capabilities
The Behind Switch mode is used when the System is connected to a PBX or
Centrex system. This other system (called the host) provides the interface to
outside lines and some features.
A Behind Switch system assigns only one line (called a prime line) to each
telephone. Outside lines to telephones or groups of telephones are assigned
through system programming.
In the Behind Switch mode, users have access to the special features of both
their system and the host system.
Different types of lines/trunks are used for the different functions of each mode.
A Key or Behind Switch system can use
Ioop-start lines
tie trunks
a DS1 facility programmed for either T1 or ISDN-PRI operation
a ground-start line only when registered under the MF FCC classification
A Hybrid/PBX system can use
Ioop-start trunks
ground-start trunks
tie trunks
Direct Inward Dialing (DID) trunks
a DS1 facility programmed for either T1 or ISDN-PRI operation
The system can provide data connections between two digital data modules
(ISDN 7500B Data Modules), between two analog modems, or between an
analog modem and a digital data module. The system can also provide access
to an in-house host computer or to a data station on a network.
Data facilities include
digital data endpoints - RS-232 and V.35 interfaces via ISDN 7500B Data
Modules
analog data endpoints - T/R modem interfaces
local host computer and workstation on local area network (LAN) access
DS1 facility interface