Specifications

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Cisco IP Telephony Network Design Guide
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Chapter 5 Dial Plan Architecture and Configuration
Special Dial String Considerations
between a local seven-digit number and a local area code to determine when the
dialing is complete. Otherwise, Cisco CallManager waits 10 seconds without
detecting any digits before assuming the dialing is complete.
Local PSTN gateway dial plan configuration is fairly simple. The gateways based
on MGCP and the Skinny Gateway Protocol have all of their dial plan information
configured in Cisco CallManager, while an H.323-based Cisco IOS gateway
typically requires only a minimal number of dial peers. These dial peers are used
by the gateway to direct all calls from Cisco CallManager to the PSTN. For an
example of this type of dial plan, see the configuration in Figure 5-8.
Outside of North America, dial strings often differ in length from one country to
another. Multiple-length dial plans present a challenge in that Cisco CallManager
does not know when dialing is complete unless you have a specific route pattern.
Cisco CallManager by default waits 10 seconds without receiving any digits
before assuming dialing is complete. The following two common options apply to
configuring a route pattern for PSTN access outside of North America. The local
PSTN access code, 0 (zero), is commonly used.
Option 1: Route Pattern = 0.!
By reducing the idle digit wait timer (to 3 seconds, for example) in the
Cisco CallManager service parameters, a call can be sent without having to wait
the full 10 seconds. The risk of this practice, however, is that Cisco CallManager
can prematurely determine that the dialing is finished if the user simply pauses in
the midst of dialing.
0. Represents the local PSTN access code.
! Stands for any digit and any number of digits. This also means that
Cisco CallManager must wait 10 seconds (the default) without receiving
any digits before it assumes the dialing is complete and sends the call.