Aastra OpenCom 100 Mounting And Commissioning User Manual page 15

Features
Further information regarding these configuration options can be found in the
chapters PBX Cascading starting on page 148 and PBX Networking starting on
page 153.
Packet Data in the D Channel
Some business applications, for instance POS terminals, cash registers or credit
card terminals, require a permanent data connection over the X.25 packet data
network. Packet data transfer through the ISDN D channel (according to X.31 via
SAPI 16) can also be established between several S interfaces of the
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OpenCom 100. Simultaneous connections are distinguished by means of a TEI
(Terminal Endpoint Identifier).
X.31 packet data can be forwarded between two S interfaces (for instance an
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internal and external S interface). Equally, data can be forwarded ("routed") over
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permanent Q.SIG lines. Data can also be routed over an S interface. It is possible
2M
to operate multiple terminals with the same TEI on different internal S interfaces.
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A TEI mapping table allows these X.31 connections to be routed to the same
external S interface.
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The routing table for X.31 packet data is set in the Configurator under Telephony:
Extended: X.31. Additional information can be found in the Configurator online
help files.
Internet Access
It is possible to connect individual PCs to the OpenCom 100 via the internal S
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ports, or to connect an entire LAN to the OpenCom 100 via the Ethernet port.
These PCs can access the Internet via the OpenCom 100. If Internet access is
already available from an Internet service provider, this can be configured in the
OpenCom 100. If the client network is not IP-capable, the OpenCom 100 can
administer the IP configuration necessary for Internet access. The OpenCom 100
has an integrated DHCP server and a DNS server, which in this case take over IP
address administration and name resolution for the client PCs.
The OpenCom 100 enables Internet access for all connected PCs by means of a
common IP address. Only this is externally visible. The local IP addresses of the
client PCs are translated to the IP address of the OpenCom 100 by network address
translation (NAT). In this way the client PCs in the LAN cannot be reached directly
from the Internet. This protects them from direct external attack. The LAN is addi-
tionally protected by the OpenCom 100 filter lists, which can be customised indi-
vidually (firewall function).
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