AT&T DEFINITY 555-230-223 - Manual (Page 17)

Introduction
The DEFINITY LAN Gateway system assembly can be distinguished from
the DEFINITY AUDIX system assembly by the ‘‘TN’’ codes on the circuit
packs and by a DEFINITY LAN Gateway label. The DEFINITY AUDIX
system assembly uses TN566 (not shipped on new systems), TN566B,
TN567, and TN2169 or TN2170. The DEFINITY LAN Gateway system
assembly uses TN2170 and TN2208.
The TN2170 circuit pack supports a hard disk, Ethernet controller, and
removable media. It also supports a serial port, an additional analog modem port,
and remote maintenance hardware.
The TN2208 circuit pack supports a 32Mhz 486SLC Central Processing Unit
(CPU) with 16MB of fixed (non-socketed) memory. It has 2 serial ports and a
user interface/Liquid Crystal Display (LCD) panel. Naturally, it also has an
interface to DEFINITY call control and switching fabric.
System Software
The software that provides the DEFINITY LAN Gateway application on the
system assembly comes preloaded on the system when it is shipped from the
factory. It is also supplied on removable media that can be reinstalled or used to
upgrade an existing system.
The function of the software is to act as a mapper (or brouter) for ASAI
messages. It links an ISDN network (DEFINITY call control) to a TCP/IP
network (computer client) by moving ASAI messages back and forth from Q.921
synchronous data frames to TCP/IP Ethernet packets. It also associates
computer clients (by their TCP/IP network addresses) to physical ports on
DEFINITY that are administered as ASAI extensions.
This mapping provides a virtual point-to-point connection between a particular
computer client and an associated port on DEFINITY. This arrangement
continues to support the ASAI ability to sense when a particular computer client
connection is lost and send an alarm. It also provides a more secure
environment by fixing the addresses of the clients that may receive
DEFINITY LAN Gateway service.
1-4 Issue 1 January 1996