3Com 3C10111C - NBX 100 - Modular Exp Base, Руководство по установке

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162 C
HAPTER
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ONFIGURING
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ELEPHONY
reliable audio, the link must support throughput of at least 64 Kbps. An
example is a single B channel of a Basic Rate Interface (BRI) ISDN line or a
single channel on a T1 line.
An ISDN connection is not the only method of connecting a remote
telephone. The ability of NBX systems to operate in Ethernet (Layer 2)
mode or IP (Layer 3) mode gives you several connection options such as
cable modem, frame relay, and DSL. Your 3Com NBX Voice-Authorized
Partner can help you to design a system to meet your needs.
You enable low-bandwidth communications in an NBX system at the
device level using the NBX NetSet utility.
To enable low-bandwidth communication for a telephone:
1 In the NBX NetSet - Main Menu window, click Device Configuration .
2 Click the Telephones tab. From the list of telephones, select the telephone
that you want to configure for low-bandwidth operation.
3 Click Modify . The Modify Telephone dialog box appears.
4 Click the Set All For Low Bandwidth Connection Compression check box
and then click OK .
A low-bandwidth telephone cannot play music on hold, initiate a page or
participate in conference calls.
Although the NBX NetSet utility allows you to change the method used
for compression, if you change the setting from the default, ADPCM to
None, your system cannot support voice messaging services over
low-bandwidth connections.
The rest of the configuration is done at the telephone and at the router.
At the telephone, you specify the IP address of the Call Processor. See
“Manually Configuring Telephone IP Settings” on page 157 . When your
low-bandwidth link is operational and connected to the Call Processor,
the Auto Discover process can discover and configure the telephone, or
you can manually configure it through the NBX NetSet utility.
You can operate with the link “always open” or you can set it up to
autodial. With an autodial connection, when you lift the receiver on the
telephone, the ISDN router or terminal adapter establishes the link to the
Call Processor. 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