Discard Digit Instructions

Table of contents:

Discard Digit Instructions (DDIs) allow conversions of a dialed number specific to a national numbering plan. Typically, companies use a route pattern such as 9.@ to access the PSTN. However, only the internal IP telephony network uses the 9 access code to reach the PSTN. If the Cisco CallManager were to keep the access code prefixed to the number to forward to the PSTN, the call would not complete. To avoid this, you can use DDIs to strip extra digits before the call reaches the PSTN.

In general, administrators apply DDIs to route patterns that contain the @ wildcard; however, you can use the DDI PreDot with route patterns that use the "." wildcard even if the route patterns do not contain the @ wildcard. Cisco CallManager applies DDIs to the called-party transformation masks at the route pattern, the route details of a route list, or a translation pattern. DDI identifiers, shown in Figure 11-6, are additive. The DDI PreDot 10-10-Dialing combines the effects of each individual identifier. Table 11-3 depicts the most commonly used DDIs in the Cisco CallManager route plan.

Figure 11-6. Digit Discard Instructions

Table 11-3. Cisco CallManager Digit Discard Instructions

You can configure DDIs at multiple places in the CallManager route plan. One of the more common places is at the route pattern configuration. As shown in Figure 11-6, you can find the DDIs under the Called Party Transformations near the end of the Route Pattern Configuration window.


Digit Discard Instructions applied at the route pattern level are visible to the end user. For example, if the caller dials 914085551212 and the DDI removes the 9, the user will see the number change to 14085551212 on the LCD display of their IP Phone. DDIs applied at the route group level (from within the route list) are not visible to the end user. Applying DDIs at the route group level is covered later in this chapter.

As you can see, CallManager offers a variety of combinations of all the DDIs listed in Table 11-3.

Transformation Masks

Part I: Cisco CallManager Fundamentals

Introduction to Cisco Unified Communications and Cisco Unified CallManager

Cisco Unified CallManager Clustering and Deployment Options

Cisco Unified CallManager Installation and Upgrades

Part II: IPT Devices and Users

Cisco IP Phones and Other User Devices

Configuring Cisco Unified CallManager to Support IP Phones

Cisco IP Telephony Users

Cisco Bulk Administration Tool

Part III: IPT Network Integration and Route Plan

Cisco Catalyst Switches

Configuring Cisco Gateways and Trunks

Cisco Unified CallManager Route Plan Basics

Cisco Unified CallManager Advanced Route Plans

Configuring Hunt Groups and Call Coverage

Implementing Telephony Call Restrictions and Control

Implementing Multiple-Site Deployments

Part IV: VoIP Features

Media Resources

Configuring User Features, Part 1

Configuring User Features, Part 2

Configuring Cisco Unified CallManager Attendant Console

Configuring Cisco IP Manager Assistant

Part V: IPT Security

Securing the Windows Operating System

Securing Cisco Unified CallManager Administration

Preventing Toll Fraud

Hardening the IP Phone

Understanding Cryptographic Fundamentals

Understanding the Public Key Infrastructure

Understanding Cisco IP Telephony Authentication and Encryption Fundamentals

Configuring Cisco IP Telephony Authentication and Encryption

Part VI: IP Video

Introducing IP Video Telephony

Configuring Cisco VT Advantage

Part VII: IPT Management

Introducing Database Tools and Cisco Unified CallManager Serviceability

Monitoring Performance

Configuring Alarms and Traces

Configuring CAR

Using Additional Management and Monitoring Tools

Part VIII: Appendix

Appendix A. Answers to Review Questions


Authorized Self-Study Guide Cisco IP Telephony (CIPT)
Cisco IP Telephony (CIPT) (Authorized Self-Study) (2nd Edition)
ISBN: 158705261X
EAN: 2147483647
Year: 2004
Pages: 329

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