3Com V3000 ANALOG, Installation Manual

Page: 190 / 252

190 C
HAPTER
10: C
ONFIGURING
IP T
ELEPHONY
NCP. In the other direction, a call to the extension of the remote
telephone initiates the connection. To ensure that there is time to
complete the call, you may need to modify the time-out values of the
system. Consult your 3Com NBX Voice-Authorized Partner or a
3Com-qualified service technician for assistance.
The specific configuration tasks required for setting up the link between
the NCP and the remote telephone depend on the type of equipment
and the Telco/ISP that you use. For help in selecting equipment and
configuring it, contact your 3Com NBX Voice-Authorized Partner or a
3Com-qualified support technician.
After you enable low-bandwidth communication for a telephone,
complete the configuration of the low-bandwidth IP connection:
1 Use the telephone key pad to configure IP settings on the telephone. See
“Manually Configuring Telephone IP Settings” on page 185 for more
information.
2 Configure the telephone in the configuration database.
Broadband Telephony NBX system software (release R4.2 and higher) supports Network Address
Port Translation (NAPT, also called NAT overloading). NAPT allows you to
put an NBX Telephone behind a device that applies network address
translation at a remote location, such as a home office, and connect to
the NCP through an Internet connection. One typical configuration is to
connect a cable/DSL modem to a small office/home office router that
includes a firewall and Ethernet ports. You connect the NBX Telephone
directly to one of the Ethernet ports.
Another option is use the NBX pcXset Soft Telephone Client instead of an
NBX Telephone. You can then use a VPN connection for your voice
connection and avoid firewall configuration problems.
This section summarizes the tasks you must complete to configure an
NBX Telephone for operation behind the NAPT device. Because the
configuration interface on each device varies, detailed procedures for
NAPT device configuration are beyond the scope of this document. For
information about configuring the NAPT device, see the documentation
for that device.