3Com NBX, Руководство по установке

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ISDN BRI Recommendations 227
ISDN BRI
Recommendations
When you work with the telephone company to install an ISDN BRI
circuit, 3Com recommends the parameters discussed in the following
sections.
■
Interface — The BRI connection supplied by the telephone company
must terminate at an S/T interface. Connections terminating at the U
interface are not supported.
■
Point-to-Point and Point-to-Multipoint — Both point-to-point and
point-to-multipoint configurations are supported.
The appropriate TEI (Terminal Endpoint Identifier) must be entered
when configuring the BRI card. Typically, Automatic TEI assignment is
used on Point-to-Multipoint lines. For Point-to-Point lines, set the TEI
value to 0 (zero).
By default the system is configured to use Automatic TEI assignment.
Thus, if the line provided is Point-to-Point, this will typically mean the
TEI has to be set to 0 (zero) when configuring.
■
DDI/MSN Applications — For DDI/MSN, 3Com recommends that
you order telephone numbers that easily fit in the NBX system
numbering plan. If possible, use 3 or 4 digit DDI/MSN codes, which
allow for simple dial plan implementation.
■
With 3 digit extensions 100-499, the last three digits of the
DDI/MSN codes should be 100-499.
■
With 4 digit extensions 1000-4999, the last four digits of the
DDI/MSN codes should be 1000-4999.
■
Supported Telephone Central Office Switch Protocols — NBX
system ISDN BRI services support the ETSI central office switch
protocol.