3Com 3C10402B, Руководство администратора

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Overview of Virtual Tie Lines 331
configured to set up the necessary VTL connection to the Dallas system,
and then to the extension at that site.
See “Dial Plan Configuration” on page 334 for more information about
how to set up VTLs in the dial plan.
VTL Connections
Using Site Codes
The simpler way to implement VTL connections uses a site code, which
consists of one or more digits that a user must dial to specify the site that
is being called. This approach requires no restriction on the telephone
extension ranges, but does require the caller to dial the site code digits as
well as the extension.
A site code can be any number of digits, but typically, one- or two-digit
numbers make the most sense. The dial plan at each site must include
appropriate routing instructions for each of the possible site code.
Figure 21 shows three sites connected by VTLs. All sites use the same
range of extension numbers (1000 through 3999). To reach someone on
another system, a user must dial a site code (61, 62, or 63 in this
example) followed by an extension.
Figure 21 Virtual Tie Lines Using Site Codes
To call someone in Atlanta, a user in Chicago must dial the site code 62
and then the appropriate extension (1000 through 3999). To reach a user
in Dallas, a user in Chicago must dial 63 and then the appropriate
extension (1000 through 3999). Because the extension is preceded by the
WAN
Chicago
System
Extensions
1000 – 3999 Atlanta
System
Extensions
1000 – 3999
Dallas
System
Extensions
1000–3999
Site Code 61
Site Code 63
Site Code 62