Worldwide [change] |Account |Register |About Cisco
Guest

Hierarchical Navigation

Support

Configuring Hardware Echo Cancellation

Downloads

Table Of Contents

Configuring Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

Prerequisites for Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

Cisco IOS Image

Baseboard and Daughter Card Configuration

Hardware Echo Cancellation Tail Length

Information About Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

How to Configure Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

Examples


Configuring Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

The multiflex trunk (MFT) dedicated echo cancellation modules (dedicated ECAN modules) are daughter cards that attach to the second generation multiflex voice/WAN interface cards (MFT VWIC2 family). The dedicated ECAN modules are available in 32-channel and 64-channel configurations (EC-MFT-32 and EC-MFT-64), which match the requirements of the 1- and 2-port T1/E1 MFT VWIC2s, respectively. This chapter describes the configuration to enable additional echo cancellation effectiveness:

•Control of the echo canceller provided through the size of the echo cancellation buffer, ranging from 24 milliseconds (ms) to 128 ms

•Processing and memory resources to ensure robust echo canceller coverage independent from the configuration of the echo canceller or the demand placed on the general voice DSP resources

Prerequisites for Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

Cisco IOS Image

To run hardware echo cancellation on T1/E1 interfaces, you must install an IP Plus or IP Voice image (minimum) of Cisco IOS Release 12.3(14)T or a later release.

Baseboard and Daughter Card Configuration

Hardware echo cancellation is restricted to the same baseboard voice/WAN interface card (VWIC) on which the daughter card (EC-MFT-32 and EC-MFT-64) is installed and cannot be shared by other T1/E1 controllers.

Hardware Echo Cancellation Tail Length

If you are using hardware echo cancellation, the value for tail length is set to 128 ms. This is not configurable and cannot be changed.

Information About Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

Table 10 lists the names and descriptions of the baseboard modules and daughter cards that offer hardware echo cancellation on T1/E1 multiflex voice/WAN interface cards.

Table 10 Modules with T1/E1 Multiflex Voice/WAN Interface Cards with Echo Cancellation Functionality

Module Name
Description

Baseboard

VIC2-1MFT-T1/E11

1-port RJ-48 multiflex voice trunk (T1/E1)

VIC2-2MFT-T1/E11

2-port RJ-48 multiflex voice trunk (T1/E1)

VWIC2-1MFT-T1/E1

1-port RJ-48 multiflex voice/WAN trunk (T1/E1)

VWIC2-2MFT-T1/E1

2-port RJ-48 multiflex voice/WAN trunk (T1/E1)

VWIC2-1MFT-G7032

1-port RJ-48 multiflex trunk (E1 G.703)

VWIC2-2MFT-G7032

2-port RJ-48 multiflex trunk (E1 G.703)

Daughter cards for hardware echo cancellation

EC-MFT-32

32-channel echo canceller module for multiflex trunk

EC-MFT-64

64-channel echo canceller module for multiflex trunk

1 The VIC2-1MFT-T1/E1 and VIC2-2MFT-T1/E1 voice modules do not support WAN connectivity.

2 Although unstructured G.703 operation is particular to E1 operation, the VWIC2-1/2MFT-G703 cards also support structured T1 operation.


Figure 16 shows a sample network topology with a Cisco 3725 router using hardware echo cancellation.

Figure 16 Sample Network Topology for the T1/E1 Multiflex Voice/WAN Interface Cards with Echo Cancellation Module

How to Configure Hardware Echo Cancellation on T1/E1 Multiflex Voice/WAN Interface Cards

To configure hardware echo cancellation on T1/E1 multiflex voice/WAN interface cards, complete the following tasks.

SUMMARY STEPS

1. enable

2. configure terminal

3. card type {e1 | t1} slot subslot

4. voice-card slot

5. voice-port {slot-number/subunit-number/port | slot/port:ds0-group-number}

6. echo-cancel enable type [hardware | software]

7. echo-cancel coverage {24 | 32 | 48 | 64}

8. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

card type {e1 | t1} slot subslot

Example:

Router(config)# card type t1 1 0

Sets or changes the card type to E1 or T1.

•slot—Specifies the slot number. Range can be 0 to 6, depending on the platform.

•subslot—Specifies the VWIC slot number. Range can be 0 to 3, depending on the host module or platform.

•When the command is used for the first time, the configuration takes effect immediately.

•A subsequent change in the card type will not take effect unless you enter the reload command or reboot the router.

Note When you are using the card type command to change the configuration of an installed card, you must enter the no card type {e1 | t1} slot subslot command first. Then enter the card type {e1 | t1} slot subslot command for the new configuration information.

Step 4 

voice-card slot

Example:

Router(config)# voice card 1

Enters voice card configuration mode.

•Specify the slot location using a value from 0 to 5.

Step 5 

voice-port {slot-number/subunit-number/port | slot/port:ds0-group-number}

Example:

Router(voice-card)# voice-port 3/0:0

Enters voice port configuration mode and specifies the voice port.

•The slot-number argument identifies the slot where the voice interface card (VIC) is installed. Valid entries are from 0 to 3, depending on the slot in which it has been installed.

•The subunit-number identifies the subunit on the VIC where the voice port is located. Valid entries are 0 or 1.

•The port argument identifies the voice port number. Valid entries are 0 and 1.

or

•The slot argument is the slot in which the voice port adapter is installed. Valid entries are from 0 to 3.

•The port argument is the voice interface card location. Valid entries are 0 to 3.

•The ds0-group-number argument indicates the defined DS0 group number. Each defined DS0 group number is represented on a separate voice port. This allows you to define individual DS0s on the digital T1/E1 card.

Step 6 

echo-cancel enable type [hardware | software]

Example:

router(config-voiceport)# echo-cancel enable type hardware

Enables hardware echo cancellation.

•The hardware keyword is the default. Echo cancel coverage is hardcoded for 128 ms.

•This command is needed only to configure the software keyword to effect software-based (DSP) echo cancellation or to restore the hardware default.

Note The hardware and software keywords are available only when the optional hardware echo cancellation module (EC-MFT-32 or EC-MFT-64) is installed on the multiflex VWIC.

Step 7 

echo-cancel coverage {24 | 32 | 48 | 64}

Example:

Router (config-voiceport) # echo-cancel coverage 24

Adjusts the echo canceller by the specified number of milliseconds.

•These coverage options are applicable only if you configured the echo-cancel enable type software command in the previous step.

•If you configured the echo-cancel enable type hardware command in the previous step, this value is set to 128 ms.

•The default for software echo cancellation is 64 ms.

Step 8 

exit

Example:

Router(config-voiceport)# exit

Exits controller cofiguration mode and returns the router to privileged EXEC mode.

Examples

This section provides the following examples for verifying echo cancellation:

•show echo-cancel hardware status: Example

•show call active voice echo-canceller summary: Example

•show call active voice echo-canceller CallID: Example

show echo-cancel hardware status: Example

The output in this section shows that hardware echo cancellation is enabled on slot 1. 

Router_3725# show echo-cancel hardware status 1   

VWIC HWECAN 1/0 is UP.

Software version:4.4.803 , Date:Feb  6 16:58:57 2004

Tail length:128     Tone disabler type:G.165    Fax notify: Off

Device:VWIC_8MBPS_1TIEC_TL128_MS_1P  Max Channels:32

Only Port0 have Local HWECAN Connectivity.


ECAN CH

ASSIGNED

DSP ID

VOICEPORT

EC

NLP

COV

LAW

========================================================================================

1

yes

1/1

1/0:1.1

on

off

on

u-Law



Total assigned channel(s):1

Total device(s) in the slot 1

show call active voice echo-canceller summary: Example

The output in this section shows summary information for the hardware echo cancellation. 

Router_3725# show call active voice echo-canceller summary 


Call ID

Port

DSP/Ch

Codec

Ecan-type

Tail

Called #

Dial-peers

========================================================================================

0xE71

1/0:1.1

1/1

g729r8

HW

128ms

1000

1/10



1 active call found

number of hardware ecan channels:1

number of software ecan channels:0

show call active voice echo-canceller CallID: Example

The output in this section shows hardware echo canceller information for an active voice call. 

Router# show call active voice echo-canceller E71

Device:VWIC HWECAN 1/0 Channel Id = 1 Tail = 128Ms

Software version:4.4.803 , Date:Feb  6 16:58:57 2004

        Echo Canceller:On   Tail-length:128ms

        H-Register:Update   Modem tone disable:Ignore 2100Hz tone

        Worst ERL :6dB     Residual Control:Cancel only

        High level compensation:Off

        Tx Power = 0.0dB  Tx Avg Power = 0.0dB

        Rx Power = 0.0dB  Rx Avg Power = 0.0dB

        ERL = 1.0dB     ACOM = 0.0

        3 Reflectors(Tails) = (90, 0, 0)Ms, Max Reflector = 90Ms

        Ecan Status words 0x1C, 0x00

        EC Lib version:9155

More detailed syntax information about the commands used with this feature is documented in the Cisco IOS Release 12.4 Voice Command Reference.