Cisco 1700 Series Modular Access Routers

Table Of Contents

Configuring 2-Port ISDN BRI Voice Interface Cards for the Cisco 1751 and Cisco 1760 Routers

Overview of ISDN BRI VICs

Configuring the Voice Interface

Configuring the BRI Layer 1

Configuring the ISDN Protocol

Turning the Line Power On and Off

TDM Clock Configuration

Configuration Example

Debugging Commands

Related Documentation

Obtaining Documentation

Cisco.com

Documentation CD-ROM

Ordering Documentation

Documentation Feedback

Obtaining Technical Assistance

Cisco.com

Technical Assistance Center

Cisco TAC Website

Cisco TAC Escalation Center

Obtaining Additional Publications and Information

Configuring 2-Port ISDN BRI Voice Interface Cards for the Cisco 1751 and Cisco 1760 Routers

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This document describes the software configuration of dual-port ISDN Basic Rate Interface (BRI) voice interface cards (VICs) for the Cisco 1751 and Cisco 1760 routers.

The information in this document applies to the following Cisco VICs:

•VIC-2BRI (NT/TE)

•VIC2-2BRI (NT/TE)

This document contains the following sections:

•Overview of ISDN BRI VICs

•Configuring the Voice Interface

•Configuration Example

•Debugging Commands

•Related Documentation

•Obtaining Documentation

•Obtaining Technical Assistance

Overview of ISDN BRI VICs

ISDN BRI VICs provide digital connectivity for voice-over-IP (VoIP) networks using the European Telecommunications Standards Institute (ETSI) Net3 switch type. BRI VICs present an ISDN S/T physical interface that connects to a network termination (NT) or terminal equipment (TE) device. With ISDN BRI VICs, you can connect a Cisco 1751 or Cisco 1760 router to a private branch exchange (PBX) network in NT or TE mode, or to a public switched telephone network (PSTN) in TE mode.

Each of the two BRI ports can operate in NT mode as the clock source or can operate in TE mode as a clock slave.

•When a VIC port operates in NT mode, it sources a clock to the BRI interface (a PBX trunk card, for example) which is operating in TE mode.

•When a VIC port operates in TE mode, it receives a clock from the BRI interface (a PBX line card, for example) which is operating in NT mode.

Figure 1 Example of Network Using Voice Interfaces

Configuring the Voice Interface

Configuring the VIC for your router requires using the Cisco IOS command-line interface (CLI). The following sections describe the procedures for enabling and configuring the voice interface:

•Configuring the BRI Layer 1

•Configuring the ISDN Protocol

•Turning the Line Power On and Off

•TDM Clock Configuration

Configuring the BRI Layer 1

At the BRI Layer 1, you can configure each port of the VIC to operate in NT (clock source) or TE (clock slave) mode by using the Cisco IOS isdn layer1-emulate command in interface configuration mode:

isdn layer1-emulate {network | user}

where network enables the VIC to operate in the NT mode, and user enables it to operate in the TE mode. The default setting for each port is the TE mode.

Configuring the ISDN Protocol

You can configure the Layer 2 protocol to operate in either NT or TE mode. Use the isdn protocol-emulate command in interface configuration mode:

isdn protocol-emulate {network | user}

where network enables the ISDN Layer 2 to operate in the NT mode, and user enables it to operate in the TE mode. The default setting is the TE mode.

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Note The configurations of Layer 1 and Layer 2 are independent of each other. For example, you can set the Layer 1 operating mode to NT and set the Layer 2 mode to TE.

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Turning the Line Power On and Off

To control the line power (phantom power only) being supplied to a connected device, use the line_power command in interface configuration mode:

line_power

no line_power

These commanda are valid only for a BRI port operating in NT mode. If a port is equipped with hardware to supply line power, using the line_power command activates line power provision from that port.

TDM Clock Configuration

For information on how to configure the time-division multiplexing (TDM) clock on the ISDN BRI VICs, refer to the following configuration note:

•Clock Configuration for Cisco 1751/1760 Routers

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Note If the VIC loses its external clock source—for example, when the ISDN line is down—the internal clock source takes over until the external clock is functioning again.

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Configuration Example

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Note Before you configure a port on the VIC, verify that the BRI interface is shut down and that the cable to the connected device is properly installed for the operating mode of the interface that you plan to configure.

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To configure each BRI interface, follow these steps, beginning in privileged EXEC mode:

	Command	Purpose
Step 1	router# configure terminal	Enters the global configuration mode.
Step 2	router(config)# isdn switch-type {basic-net3 | basic-qsig}	Specifies the ISDN switch type.
Step 3	router(config)# tdm clock bri-auto or router(config)# tdm clock bri <slot/port> export and/or router(config)# tdm clock bri <slot/port> import {T1 | E1 | atm | bri | onboard} <slot/port>	Configures automatic TDM selection for the BRI VIC. Configures the BRI port that exports the TDM clock. Configures the BRI port(s) that import(s) the TDM clock.
Step 4	router(config)# interface bri 0/0	Changes to interface configuration mode for port 0 in slot 0.
Step 5	router(config-if)# no ip address	Specifies that there is no IP address for this interface.
Step 6	router(config-if)# shutdown router(config-if)# isdn layer1-emulate {user | network} router(config-if)# no shutdown	Shuts down the interface. Configures the Layer 1 port mode and clock settings: •Enter user to configure the port as TE and to function as a clock slave. This is the default. •Enter network to configure the port as NT and to function as a clock master. Activates the interface after the port configuration.
Step 7	router(config-if)# line-power	(Optional only for NT-configured ports.) Turns on the power supplied from the port to a TE device.
Step 8	router(config-if)# isdn protocol-emulate {user | network}	Configures the Layer 2 port protocol emulation: •Enter user to configure the port as TE so that the PBX is the master. This is the default. •Enter network to configure the port as NT so that the PBX is the slave.
Step 9	router(config-if)# end	Exits configuration mode.

Debugging Commands

Use the following commands to debug your configuration:

•debug bri

•debug isdn q921

•debug isdn q931

•debug isdn events

•show isdn status bri

•show controller bri

•show interfaces bri

For more information about these commands, see the Cisco IOS documentation.

Related Documentation

The document is to be used with the following documents:

•Cisco Interface Cards Hardware Installation Guide

•Cisco 1751 Router Hardware Installation Guide

•Cisco 1751 Router Software Configuration Guide

•Cisco 1760 Modular Access Router Hardware Installation Guide

•Quick Start Guide for Installing Your Cisco 1760 Modular Access Router

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This document is to be used in conjunction with the documents listed in the "Related Documentation" section.

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