3Com 3C10402B, Руководство администратора

Страница: 270 / 582

270 C
HAPTER
11: D
IAL
P
LAN
Example: Assign one extension range to Company A and a different
range to Company B. The fourth table controls the extension range for
Company B, so that outbound calls from Company B’s extensions use
only their external telephone lines.
You might need a fourth table if a company has two sites but only one
system. To route emergency (911) calls properly, use the fourth table to
define which extensions use each dedicated 911 telephone line.
Example: Telephone users at Site A dial 911 and the system uses the
Internal table (table ID 1) to make the emergency call on one external
telephone line. Users at Site B dial 911 and the system uses table ID 4 to
make the emergency call on a different external telephone line. The
emergency staff know, based on the dialing number, which site has the
emergency.
Enhanced 911, E911, is available in some areas. This service enables
emergency staff to identify the specific location of the emergency. For
example, in a campus of buildings, the emergency staff can identify the
specific building, floor, and location from which the emergency call
originates. The system supports E911 over ISDN. You must define an
outbound call pretranslator to provide the specific extension number
from which the 911 call originates.
Dial Plan
Pretranslators
The system uses pretranslators to modify digit sequences of incoming or
outgoing calls. On incoming calls, pretranslators can map the entire
dialed number (including area code) to an internal extension number.
For example, an external caller dials 978-555-0101 to reach the person
on extension 101. Pretranslators ensure that the proper digits are
mapped to the correct extension number.
For more information, see:
■
Pretranslators for Incoming Calls on page 271
■
Pretranslators for Certain Outgoing Calls on page 272
A typical pretranslator function involves mapping incoming DDI/DID
telephone calls to internal extension numbers.
Example: The DDI/DID telephone numbers range from 508-555-4200
through 508-555-4299. The telephone company sends you the last