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Fine-Tuning Analog and Digital Voice Ports
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Fine-Tuning Analog and Digital Voice Ports

Table Of Contents

Fine-Tuning Analog and Digital Voice Ports

Information About Fine-Tuning Analog and Digital Voice Ports

How to Configure Fine-Tuning Features for Analog and Digital Voice Ports

Configuring Channel Bank Support for T1/E1 Voice Ports

Restrictions for Channel Bank Support

Configuring Auto Cut-Through

Modifying Bit Patterns for Digital Voice Ports

Configuring ANI for Outbound Calling

Configuring Disconnect Supervision

Configuring FXO Supervisory Disconnect Tones

Configuring Timeouts Parameters

Changing Timing Parameters

Configuring the DTMF Timer

Configuring Comfort Noise and Music Threshold for VAD


Fine-Tuning Analog and Digital Voice Ports


The default parameter values for voice ports are usually sufficient for most networks. Depending on the specifics of your particular network, however, you may need to adjust certain parameters that are configured on voice ports. Collectively, these commands are referred to as voice port tuning commands.


Note The commands, keywords, and arguments that you are able to use may differ slightly from those presented here, based on your platform, Cisco IOS release, and configuration. When in doubt, use Cisco IOS command help to determine the syntax choices that are available.


Information About Fine-Tuning Analog and Digital Voice Ports

This section provides basic information about some the features that can be fine-tuned to improve the performance of your voice network:

Channel Bank Support for T1/E1 Voice Ports—Provides support for the time-division multiplexing (TDM) cross-connect functionality between analog voice ports and digital DS0s on the same NM-HD-2VE using channel associated signaling (CAS).

Auto Cut-Through—Allows you to connect to PBXs that do not provide an M-lead response.

Modification of Bit Patterns for Digital Voice Ports—Enables commands for digital voice ports to modify sent or received bit patterns. Different versions of E&M use different ABCD signaling bits to represent idle and seize.

ANI for Outbound Calling—Allows the automatic number identification (ANI) to be sent for outgoing calls on the Cisco AS5300 (if T1 CAS is configured with the Feature Group-D (FGD)—Exchange Access North American (FGD-EANA) signaling).

Disconnect Supervision—Configures the router to recognize the type of signaling in use by the PBX or PSTN switch connected to the voice port. These methods include the following:

Battery reversal disconnect

Battery denial disconnect

Supervisory tone disconnect (STD)

FXO Supervisory Disconnect Tones—Prevents an analog FXO port from remaining in an off-hook state after an incoming call is ended. FXO supervisory disconnect tone enables interoperability with PSTN and PBX systems whether or not they transmit supervisory tones.

Timeouts Parameters—Modifies values for timeouts. For example, you can adjust the wait time for the caller input of the initial digit and the subsequent digit of the dialed string. If the wait time expires before the destination is identified, a tone sounds and the call ends.

Timing Parameters—Changes a wide range of timing values. For example, you can specify the minimum delay time, in milliseconds, from outgoing seizure to outdial address.

DTMF Timer—Modifies the value for the DTMF interdigit timer.

Comfort Noise and Music Threshold for VAD—Specifies the minimal decibel level of music played when calls are put on hold and creates subtle background noise to fill silent gaps during calls when VAD is enabled on voice dial peers. If comfort noise is not generated, the resulting silence can fool the caller into thinking the call is disconnected instead of being merely idle.

How to Configure Fine-Tuning Features for Analog and Digital Voice Ports

To configure the voice port tuning features for analog and digital voice ports, complete these tasks:

Configuring Channel Bank Support for T1/E1 Voice Ports

Configuring Auto Cut-Through

Modifying Bit Patterns for Digital Voice Ports

Configuring ANI for Outbound Calling

Configuring Disconnect Supervision

Configuring FXO Supervisory Disconnect Tones

Configuring Timeouts Parameters

Changing Timing Parameters

Configuring the DTMF Timer

Configuring Comfort Noise and Music Threshold for VAD


Note The commands, keywords, and arguments that you are able to use may differ slightly from those presented here, based on your platform, Cisco IOS release, and configuration. When in doubt, use Cisco IOS command help to determine the syntax choices that are available. Full descriptions of the commands in this section can be found in the Cisco IOS Voice Command Reference.


Configuring Channel Bank Support for T1/E1 Voice Ports

The channel bank feature provides support for the time-division multiplexing (TDM) cross-connect functionality between analog voice ports and digital DS0s on the same NM-HD-2VE using channel associated signaling (CAS).

To establish a channel bank connection between an analog voice port and a T1 DS0, configure the connect (voice-port) command in global configuration mode. To verify the channel bank connection, use the show connection all command.

Restrictions for Channel Bank Support

The configuration for cross-connect must be on the same network module.

A maximum of four Foreign Exchange Service (FXS) or Foreign Exchange Office (FXO) ports can be cross-connected to a T1 interface.

A BRI-to-PRI cross-connect cannot be configured.

Analog-to-BRI/PRI cross-connect cannot be configured; the only connection for analog is analog-to-T1/E1 CAS (ds0-group).

The local-bypass command has no effect when cross-connect is configured. It is applicable only to calls that are hairpinned via POTS-to-POTS dial peers.

The DS0 group must contain only one time slot. The signaling type of the DS0 group must match that of the analog voice port.

If the channel bank feature is used for the T1 controller, the rest of the unused DS0 group cannot be used for fractional PRI signaling.

SUMMARY STEPS

1. enable

2. configure terminal

3. controller {t1 | e1} slot/port

4. ds0-group ds0-group-number timeslots timeslot-list type {e&m-delay-dial | e&m-fgd | e&m-immediate-start | e&m-wink-start | fxo-ground-start | fxo-loop-start | fxs-ground-start | fxs-loop-start}

5. exit

6. voice-port slot/port

7. operation {2-wire | 4-wire}

8. type {1 | 2 | 3 | 5}

9. signal {loop-start | ground-start}

or

signal {wink-start | immediate | delay-dial}

10. exit

11. connect connection-name voice-port voice-port-number {t1 | e1} controller-number ds0-group-number

12. 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 

controller {t1 | e1} slot/port

Example:

Router(config)# controller t1 1/0

Enters controller configuration mode and identifies the controller type (T1 or E1) and a slot and port for configuration commands that specifically apply to the T1 or E1 interface.

Valid values for the slot and port arguments are 0 and 1.

Step 4 

ds0-group ds0-group-number timeslots 
timeslot-list type {e&m-delay-dial | e&m-fgd | 
e&m-immediate-start | e&m-wink-start | 
fxs-ground-start | fxs-loop-start | 
fxo-ground-start | fxo-loop-start}
Example:

Router(config-controller)# ds0-group 1 timeslots 1 type e&m-wink-start

Defines the T1 or E1 channels for use by compressed voice calls and the signaling method the router uses to connect to the PBX or central office (CO).

The ds0-group command automatically creates a logical voice port.

ds0-group-number—Value from 0 to 23 that identifies the DS0 group.

timeslot-list—Single number, numbers separated by commas, or a pair of numbers separated by a hyphen to indicate a range of time slots. For T1, allowable values are 1 to 24; for E1, allowable values are 1 to 31.

The signaling method selection for type depends on the connection that you are making:

Ear and Mouth (E&M) connects PBX trunk lines (tie lines) and telephone equipment. The wink and delay settings both specify confirming signals between the sending and receiving ends, or the immediate setting stipulates no special off-hook/on-hook signal.

FXO connects a CO to a standard PBX interface where permitted by local regulations.

FXS connects basic telephone equipment and PBXs.

Step 5 

exit

Example:

Router(config-controller)# exit

Exits controller configuration mode and returns to global configuration mode.

Step 6 

voice-port slot/port

Example:

Router(config)# voice-port 2/1

Enters voice-port configuration mode and identifies a slot and port for configuration parameters.

Step 7 

operation {2-wire | 4-wire}

Example:

Router(config-voiceport)# operation 4-wire

Selects a specific cabling scheme for E&M ports:

This command is not applicable to FXS or FXO interfaces because they are, by definition, 2-wire interfaces.

Using this command on a voice port changes the operation of both voice ports on a VPM card. The voice port must be shut down and then opened again for the new value to take effect.

Step 8 

type {1 | 2 | 3 | 5}

Example:

Router(config-voiceport)# type 2

Specifies the E&M interface type.

Step 9 

signal {loop-start | ground-start}


or

signal {wink-start | immediate | delay-dial}

Example:

Router(config-voiceport)# signal loop-start

or

Router(config-voiceport)# signal wink-start

Defines the signal type to be used.

Step 10 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and returns to global configuration mode.

Step 11 

connect connection-name voice-port voice-port-number {t1 | e1} controller-number ds0-group-number

Example:

Router(config)# connect connect1 voice-port 1/1/0 t1 1/0 0

Creates a named connection between two voice ports associated with T1 or E1 interfaces where you have already defined the groups by using the ds0-group command.

Step 12 

exit

Example:

Router(config)# exit

Exits the current configuration session and returns to privileged EXEC mode.

Configuring Auto Cut-Through

The auto-cut-through command allows you to connect to PBXs that do not provide an M-lead response. To configure auto-cut-through, complete the following task:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. auto-cut-through

5. 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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

auto-cut-through

Example:

Router(config-voiceport)# auto-cut-through

(E&M only) Enables call completion on a router if a PBX does not provide an M-lead response.

Step 5 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Modifying Bit Patterns for Digital Voice Ports

The bit modification commands for digital voice ports modify sent or received bit patterns. Different versions of E&M use different ABCD signaling bits to represent idle and seize. For example, North American CAS E&M represents idle as 0XXX and seize as 1XXX, where X indicates that the state of the BCD bits is ignored. In MELCAS E&M, idle is 1101 and seize is 0101.

To manipulate bit patterns to match particular E&M schemes, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. condition {tx-a-bit | tx-b-bit | tx-c-bit | tx-d-bit} {rx-a-bit | rx-b-bit | rx-c-bit | rx-d-bit} {on | off | invert}

5. define {tx-bits | rx-bits} {seize | idle} {0000 | 0001 | 0010 | 0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 | 1011 | 1100 | 1101 | 1110 | 1111}

6. ignore {rx-a-bit | rx-b-bit | rx-c-bit | rx-d-bit}

7. exit

DETAILED STEPS

 
Command
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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

condition {tx-a-bit | tx-b-bit | tx-c-bit | tx-d-bit} {rx-a-bit | rx-b-bit | rx-c-bit | rx-d-bit} {on | off | invert}

Example:

Router(config-voiceport)# condition tx-a-bit on

Manipulates sent or received bit patterns to match expected patterns on a connected device. Repeat the command for each transmit or receive bit to be modified, but be careful not to destroy the information content of the bit pattern.

The default is that the signaling format is not manipulated (for all transmit or receive A, B, C, and D bits).

Note The show voice port command reports at the protocol level, and the show controller command reports at the driver level. The driver is not notified of any bit manipulation using the condition command. As a result, the show controller command output does not account for the bit conditioning.

Step 5 

define {tx-bits | rx-bits} {seize | idle} {0000 | 0001 | 0010 | 0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 | 1011 | 1100 | 1101 | 1110 | 1111}

Example:

Router(config-voiceport)# define tx-bits seize 0000

(Digital E1 E&M voice ports on Cisco 2600 and Cisco 3600 series routers only) Defines specific transmit or receive signaling bits to match the bit patterns required by a connected device for North American E&M and E&M MELCAS voice signaling, if patterns different from the preset defaults are required.

Also specifies which bits a voice port monitors and which bits it ignores, if patterns that are different from the defaults are required.

See the define command for the default signaling patterns as defined in American National Standards Institute (ANSI) and European Conference of Posts and Telecommunication Administration (CEPT) standards.

Step 6 

ignore {rx-a-bit | rx-b-bit | rx-c-bit | rx-d-bit}

Example:

Router(config-voiceport)# ignore rx-a-bit

(Digital E1 E&M voice ports on Cisco 2600 and Cisco 3600 series routers only) Configures the voice port to ignore the specified receive bit for North American E&M or E&M MELCAS, if patterns different from the defaults are required. See the Cisco IOS Voice Command Reference for the default signaling patterns as defined in ANSI and CEPT standards.

Step 7 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Configuring ANI for Outbound Calling

On the Cisco AS5300 platform, if T1 CAS is configured with the Feature Group-D (FGD)—Exchange Access North American (FGD-EANA) signaling, the automatic number identification (ANI) can be sent for outgoing calls by using the calling-number outbound command.

FGD-EANA is a FGD signaling protocol of type EANA, which provides certain call services, such as emergency (USA 911) calls. ANI is a Signaling System 7 (SS7) feature in which a series of digits, analog or digital, are included in the call to identify the telephone number of the calling device. In other words, ANI identifies the number of the calling party. ANI digits are used for billing purposes by Internet service providers (ISPs), among other things. The commands in this section can be issued in voice-port or dial-peer configuration mode, because the syntax is the same.

To configure your digital T1/E1 packet voice trunk network module to generate outbound ANI digits on a Cisco AS5300, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. calling-number outbound range string1 string2

5. calling-number outbound sequence [string1] [string2] [string3] [string4] [string5]

6. calling-number outbound null

7. exit

DETAILED STEPS

 
Command
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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

calling-number outbound range string1 string2

Example:

Router(config-voiceport)# calling-number outbound range 3000 4000

(Cisco AS5300 only) Specifies ANI to be sent out when the T1-CAS fgd-eana command is configured as signaling type. The string1 and string2 arguments are valid E.164 telephone number strings. Both strings must be of the same length and cannot be more than 32 digits long.

Only the last four digits are used for specifying the range (string1 to string2) and for generating the sequence of ANI by rotating through the range until string2 is reached and then starting from string1 again. If strings are fewer than four digits in length, then entire strings are used.

Step 5 

calling-number outbound sequence [string1] [string2] [string3] [string4] [string5]

Example:

Router(config-voiceport)# calling-number outbound sequence 2000 3000 4000

(Cisco AS5300 only) Specifies ANI to be sent out when the T1-CAS fgd-eana command is configured as signaling type. This option configures a sequence of discrete strings (string1...string5) to be passed out as ANI for successive calls using the dial peer or voice port. Limit is five strings. All strings must be valid E.164 numbers, up to 32 digits in length.

Step 6 

calling-number outbound null

Example:

Router(config-voiceport)# calling-number outbound null

(Cisco AS5300 only) Suppresses ANI. No ANI is passed when this voice port is selected.

Step 7 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Configuring Disconnect Supervision

PBX and PSTN switches use several different methods to indicate that a call should be disconnected because one or both parties have hung up. The commands in this section are used to configure the router to recognize the type of signaling in use by the PBX or PSTN switch connected to the voice port. These methods include the following:

Battery reversal disconnect

Battery denial disconnect

Supervisory tone disconnect (STD)

Battery reversal occurs when the connected switch changes the polarity of the line in order to indicate changes in call state (such as off-hook or, in this case, call disconnect). This is the signaling looked for when the battery reversal command is enabled on the voice port, which is the default configuration.

Battery denial (sometimes called power denial) occurs when the connected switch provides a short (approximately 600 milliseconds) interruption of line power to indicate a change in call state. This is the signaling looked for when the supervisory disconnect command is enabled on the voice port, which is the default configuration.

Supervisory tone disconnect occurs when the connected switch provides a special tone to indicate a change in call state. Some PBXs and PSTN CO switches provide a 600-millisecond interruption of line power as a supervisory disconnect, and others provide STD. This is the signal that the router is looking for when the no supervisory disconnect command is configured on the voice port.


Note In some circumstances, you can use the FXO Disconnect Supervision feature to enable analog FXO ports to monitor call progress tones for disconnect supervision that are returned from a PBX or from the PSTN. For more information, see the "Configuring FXO Supervisory Disconnect Tones" section.


To change parameters related to disconnect supervision, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. no battery-reversal

5. no supervisory disconnect

6. disconnect-ack

7. exit

DETAILED STEPS

 
Command
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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

no battery-reversal

Example:

Router(config-voiceport)# no battery-reversal

(Analog only) Enables battery reversal. The default is that battery reversal is enabled.

For FXO ports—Use the no battery-reversal command to configure a loop-start voice port not to disconnect when it detects a second battery reversal. The default is to disconnect when a second battery reversal is detected.

Note This functionality is supported on Cisco 1750, Cisco 2600 series, and Cisco 3600 series routers; only analog voice ports on VIC-2FXO cards are able to detect battery reversal.

Also use the no battery-reversal command when a connected FXO port does not support battery reversal detection.

For FXS ports—Use the no battery-reversal command to configure the voice port not to reverse battery when it connects calls. The default is to reverse battery when a call is connected, then return to normal when the call is over, providing positive disconnect.

See also the disconnect-ack command (Step 6).

Step 5 

no supervisory disconnect

Example:

Router(config-voiceport)# no supervisory disconnect

(FXO only) Enables the PBX or PSTN switch to provide STD. The supervisory disconnect command is enabled by default.

Step 6 

disconnect-ack

Example:

Router(config-voiceport)# disconnect-ack

(FXS only) Configures the voice port to return an acknowledgment upon receipt of a disconnect signal. The FXS port removes line power if the equipment on the FXS loop-start trunk disconnects first. This is the default.

The no disconnect-ack command prevents the FXS port from responding to the on-hook disconnect with a removal of line power.

Step 7 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Configuring FXO Supervisory Disconnect Tones

If the FXO supervisory disconnect tone is configured and a detectable tone from the PSTN or PBX is detected by the digital signal processor (DSP), the analog FXO port goes on-hook. This feature prevents an analog FXO port from remaining in an off-hook state after an incoming call is ended. FXO supervisory disconnect tone enables interoperability with PSTN and PBX systems whether or not they transmit supervisory tones.

To configure a voice port to detect incoming tones, you need to know the parameters of the tones expected from the PBX or PSTN. Then create a voice class that defines the tone detection parameters, and, finally, apply the voice class to the applicable analog FXO voice ports. This procedure configures the voice port to go on-hook when it detects the specified tones. The parameters of the tones need to be precisely specified to prevent unwanted disconnects because of nonsupervisory tones or noise detection.

A supervisory disconnect tone is normally a dual tone consisting of two frequencies; however, tones of only one frequency can also be detected. Use caution if you configure voice ports to detect nondual tones, because unwanted disconnects can result from detection of random tone frequencies. You can configure a voice port to detect a tone with one on/off time cycle, or you can configure it to detect tones in a cadence pattern with up to four on/off time cycles.


Note In the following procedure, the following commands were not supported until Cisco IOS Release 12.2(2)T: freq-max-deviation, freq-max-power, freq-min-power, freq-power-twist, and freq-max-delay.


To create a voice class that defines the specific tone or tones to be detected and then apply the voice class to the voice port, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice class dualtone tag

4. freq-pair tone-id frequency-1 frequency-2

5. freq-max-deviation hertz

6. freq-max-power dBmO

7. freq-min-power dBmO

8. freq-power-twist dBmO

9. freq-max-delay milliseconds

10. cadence-min-on-time milliseconds

11. cadence-max-off-time milliseconds

12. cadence-list cadence-id cycle-1-on-time cycle-1-off-time [cycle-2-on-time cycle-2-off-time] [cycle-3-on-time cycle-3-off-time] [cycle-4-on-time cycle-4-off-time]

13. cadence-variation milliseconds

14. exit

15. voice-port slot/subunit/port

16. supervisory disconnect dualtone {mid-call | pre-connect} voice-class tag

17. supervisory disconnect anytone

18. exit

DETAILED STEPS

 
Command
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 

voice class dualtone tag

Example:

Router(config)# voice class dualtone 1

Enters voice-class configuration mode and creates a voice class for defining one tone detection pattern. Range is 1 to 10000. The tag number must be unique on the router.

For more information about configuring voice classes, refer to the Dial Peer Configuration onVoice Gateway Routers.

Step 4 

freq-pair tone-id frequency-1 frequency-2

Example:

Router(config-voice-class)# freq-pair 16 300 0

Specifies the two frequencies, in Hz, for a tone to be detected (or one frequency if a nondual tone is to be detected). If the tone to be detected contains only one frequency, enter 0 for frequency-2.

Note Repeat this command for each additional tone to be specified.

Step 5 

freq-max-deviation hertz

Example:

Router(config-voice-class)# freq-max-deviation 10

Specifies the maximum frequency deviation that will be detected, in Hz. Range is 10 to 125. Default is 10.

Step 6 

freq-max-power dBmO

Example:

Router(config-voice-class)# freq-max-power 20

Specifies the maximum tone power that will be detected, in dBmO. Range is 0 to 20. Default is 10.

Step 7 

freq-min-power dBmO

Example:

Router(config-voice-class)# freq-min-power 35

Specifies the minimum tone power that will be detected, in dBmO. Range is 10 to 35. Default is 30.

Step 8 

freq-power-twist dBmO

Example:

Router(config-voice-class)# freq-power-twist 15

Specifies the power difference allowed between the two frequencies, in dBmO. Range is 0 to 15. Default is 6.

Step 9 

freq-max-delay time

Example:

Router(config-voice-class)# freq-max-delay 10

Specifies the timing difference allowed between the two frequencies, in 10-millisecond increments. Range is 10 to 100 (100 ms to 1 second). Default is 20 (200 ms).

Step 10 

cadence-min-on-time time

Example:

Router(config-voice-class)# cadence-min-on-time 10

Specifies the minimum tone on time that will be detected, in 10-millisecond increments. Range is 0 to 100 (0 ms to 1 second).

Step 11 

cadence-max-off-time time

Example:

Router(config-voice-class)# cadence-max-off-time 2000

Specifies the maximum tone off time that will be detected, in 10-millisecond increments. Range is 0 to 5000 (0 ms to 50 seconds).

Step 12 

cadence-list cadence-id cycle-1-on-time cycle-1-off-time [cycle-2-on-time cycle-2-off-time] [cycle-3-on-time cycle-3-off-time] [cycle-4-on-time cycle-4-off-time]

Example:

Router(config-voice-class)# cadence-list 1 0 1000

(Optional) Specifies a tone cadence pattern to be detected. Specify an on time and off time for each cycle of the cadence pattern.

The arguments are as follows:

cadence-id—Range is 1 to 10. There is no default.

cycle-N-on-time—Range is 0 to 1000 (0 ms to 10 seconds). Default is 0.

cycle-N-off-time—Range is 0 to 1000 (0 ms to 10 seconds). Default is 0.

Step 13 

cadence-variation time

Example:

Router(config-voice-class)# cadence-variation 200

(Optional) Specifies the maximum time that the tone onset can vary from the specified onset time and still be detected, in 10-millisecond increments. Range is 0 to 200 (0 ms to 2 seconds). Default is 0.

Step 14 

exit

Example:

Router(config-voice-class)# exit

Exits voice class configuration mode.

Step 15 

voice-port slot/subunit/port

Example:

Router(config)# voice-port 0/1/0

Enters voice-port configuration mode.

Step 16 

supervisory disconnect dualtone {mid-call | pre-connect} voice-class tag

Example:

Router(config-voiceport)# supervisory disconnect dualtone mid-call voice-class 1

Assigns an FXO supervisory disconnect tone voice class to the voice port.

Step 17 

supervisory disconnect anytone

Example:

Router(config-voiceport)# supervisory disconnect anytone

Configures the voice port to disconnect on receipt of any tone.

Step 18 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Configuring Timeouts Parameters

To change timeouts parameters, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. timeouts call-disconnect seconds

5. timeouts initial seconds

6. timeouts interdigit seconds

7. timeouts ringing {seconds | infinity}

8. timeouts wait-release {seconds | infinity}

9. exit

DETAILED STEPS

 
Command
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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

timeouts call-disconnect seconds

Example:

Router(config-voiceport)# timeouts call-disconnect 60

Configures the call disconnect timeout value in seconds. Range is 0 to 120. Default is 60.

Step 5 

timeouts initial seconds

Example:

Router(config-voiceport)# timeouts initial 10

Sets the number of seconds that the system waits between the caller input of the initial digit and the subsequent digit of the dialed string. If the wait time expires before the destination is identified, a tone sounds and the call ends.

The seconds argument is the initial timeout duration. Range is 0 to 120. Default is 10.

Step 6 

timeouts interdigit seconds

Example:

Router(config-voiceport)# timeouts interdigit 10

Configures the number of seconds that the system waits after the caller has input the initial digit or a subsequent digit of the dialed string. If the timeout ends before the destination is identified, a tone sounds and the call ends. This value is important when you are using variable-length dial peer destination patterns (dial plans).

The seconds argument is the interdigit timeout wait time in seconds. Range is 0 to 120. Default is 10.

Step 7 

timeouts ringing {seconds | infinity}

Example:

Router(config-voiceport)# timeouts ringing infinity

Specifies the duration that the voice port allows ringing to continue if a call is not answered.

Default for seconds is 180.

Step 8 

timeouts wait-release {seconds | infinity}

Example:

Router(config-voiceport)# timeouts wait-release 30

Specifies the duration that a voice port stays in the call-failure state while the Cisco device sends a busy tone, reorder tone, or an out-of-service tone to the port.

Default for seconds is 30.

Step 9 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Changing Timing Parameters

To change timing parameters, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. voice-port slot/port

4. timing clear-wait milliseconds

5. timing delay-duration milliseconds

6. timing delay-start milliseconds

7. timing delay-with-integrity milliseconds

8. timing dial-pulse min-delay milliseconds

9. timing dialout-delay millisecond

10. timing digit milliseconds

11. timing guard-out milliseconds

12. timing hookflash-out milliseconds

13. timing interdigit milliseconds

14. timing percentbreak percent

15. timing pulse pulses-per-second

16. timing pulse-digit milliseconds

17. timing pulse-interdigit milliseconds

18. timing wink-duration milliseconds

19. timing wink-wait milliseconds

20. exit

DETAILED STEPS

 
Command
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 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For the syntax for your platform, refer to the Cisco IOS Voice Command Reference.

Step 4 

timing clear-wait milliseconds

Example:

Router(config-voiceport)# timing clear-wait 200

(E&M only) Specifies the minimum amount of time, in milliseconds, between the inactive seizure signal and clearing of the call.

Range is 200 to 2000. Default is 400.

Step 5 

timing delay-duration milliseconds

Example:

Router(config-voiceport)# timing delay-duration 100

(E&M only) Specifies the delay signal duration for delay-dial signaling, in milliseconds.

Range is 100 to 5000. Default is 2000.

Step 6 

timing delay-start milliseconds

Example:

Router(config-voiceport)# timing delay-start milliseconds

(E&M only) Specifies minimum delay time, in milliseconds, from outgoing seizure to outdial address.

Range is 20 to 2000. Default is 300.

Step 7 

timing delay-with-integrity milliseconds

Example:

Router(config-voiceport)# timing delay-with-integrity 0

(Cisco MC3810 E&M ports only) Specifies duration of the wink pulse for the delay dial, in milliseconds.

Range is 0 to 5000. Default is 0.

Step 8 

timing dial-pulse min-delay milliseconds

Example:

Router(config-voiceport)# timing dial-pulse min-delay 300

Specifies time, in milliseconds, between the generation of wink-like pulses when the type is pulse.

Range is 0 to 5000. Default is 300 for Cisco 3600 series and 140 for Cisco MC3810.

Step 9 

timing dialout-delay milliseconds

Example:

Router(config-voiceport)# timing dialout-delay 100

(Cisco MC3810 only) Specifies dial-out delay, in milliseconds, for the sending digit or cut-through on an FXO trunk or an E&M immediate trunk.

Range is 100 to 5000. Default is 300.

Step 10 

timing digit milliseconds

Example:

Router(config-voiceport)# timing digit 50

Specifies the DTMF digit signal duration in milliseconds.

Range is 50 to 100. Default is 100.

Step 11 

timing guard-out milliseconds

Example:

Router(config-voiceport)# timing guard-out 300

(FXO ports only) Specifies the duration in milliseconds of the guard-out period that prevents this port from seizing a remote FXS port before the remote port detects a disconnect signal.

Range is 300 to 3000. Default is 2000.

Note For Caller ID to work for FXO ports registered to a Cisco Unified CM, the range in milliseconds must be between 1000 to 2000.

Step 12 

timing hookflash-out milliseconds

Example:

Router(config-voiceport)# timing hookflash-out 500

Specifies the duration, in milliseconds, of the hookflash.

Range is 50 to 500. Default is 300.

Step 13 

timing interdigit milliseconds

Example:

Router(config-voiceport)# timing interdigit 100

Specifies the dual-tone multifrequency (DTMF) interdigit duration, in milliseconds.

Range is 50 to 500. Default is 100.

Step 14 

timing percentbreak percent

Example:

Router(config-voiceport)# timing percentbreak 20

(Cisco MC3810 FXO and E&M ports only) Specifies the percentage of the break period for the dialing pulses, if different from the default.

Range is 20 to 80. Default is 50.

Step 15 

timing pulse pulses-per-second

Example:

Router(config-voiceport)# timing pulse 20

(FXO and E&M only) Specifies the pulse dialing rate in pulses per second.

Range is 10 to 20. Default is 20.

Step 16 

timing pulse-digit milliseconds

Example:

Router(config-voiceport)# timing pulse-digit 10

(FXO only) Configures the pulse digit signal duration.

Range is 10 to 20. Default is 20.

Step 17 

timing pulse-interdigit milliseconds

Example:

Router(config-voiceport)# timing pulse-interdigit 500

(FXO and E&M only) Specifies pulse dialing interdigit timing in milliseconds.

Range is 100 to 1000. Default is 500.

Step 18 

timing wink-duration milliseconds

Example:

Router(config-voiceport)# timing wink-duration 200

(E&M only) Specifies maximum wink-signal duration, in milliseconds, for a wink-start signal.

Range is 100 to 400. Default is 200.

Step 19 

timing wink-wait milliseconds

Example:

Router(config-voiceport)# timing wink-wait 200

(E&M only) Specifies maximum wink-wait duration, in milliseconds, for a wink-start signal.

Range is 100 to 5000. Default is 200.

Step 20 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode and completes the configuration.

Configuring the DTMF Timer

To configure the DTMF timer, use the following commands:

SUMMARY STEPS

1. enable

2. configure terminal

3. controller T1 number

4. ds0-group channel-number timeslots range type signaling-type dtmf dnis

5. cas-custom channel

6. dtmf timer-inter-digit milliseconds

7. exit

DETAILED STEPS

 
Command
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 

controller T1 number

Example:

Router(config)# controller T1 1

Configures a T1 controller and enters controller configuration mode.

Step 4 

ds0-group channel-number timeslots range type signaling-type dtmf dnis

Example:

Router(config-controller)# ds0-group 0 timeslots 1-4 type e&m-immediate-start dtmf dnis

Configures channelized T1 time slots, which enables a Cisco AS5300 modem to answer and send an analog call.

Step 5 

cas-custom channel

Example:

Router(config-controller)# cas-custom 2

Enters cas-controller configuration mode and customizes signaling parameters for a particular E1 or T1 channel group on a channelized line.

Step 6 

dtmf timer-inter-digit milliseconds

Example:

Router(conf-ctrl-cas)# dtmf timer-inter-digit 100

Configures the DTMF interdigit timer for a DS0 group.

Step 7 

exit

Example:

Router(conf-ctrl-cas)# exit

Exits cas-controller configuration mode and completes the configuration.

Configuring Comfort Noise and Music Threshold for VAD

In normal voice conversations, only one person speaks at a time. Circuit-switched telephone networks dedicate a bidirectional 64 kbps channel for the duration of each conversation, regardless of whether anyone is speaking at the moment. This means that, in a normal voice conversation, at least 50 percent of the bandwidth is wasted when one or both parties are silent. This figure can actually be much higher when normal pauses and breaks in conversation are taken into account.

Packet-switched voice networks can use this "wasted" bandwidth for other purposes when voice activity detection (VAD) is configured. VAD works by detecting the magnitude of speech in decibels and deciding when to stop segmenting voice packets into frames. VAD has some technological problems, however, which include the following:

General difficulties determining when speech ends

Clipped speech when VAD is slow to detect that speech is beginning again

Automatic disabling of VAD when conversations take place in noisy surroundings

VAD is configured in dial peers; by default it is enabled. Two parameters associated with VAD, music threshold and comfort noise, are configured on voice ports.

If VAD is enabled, use the following commands to adjust music threshold and comfort noise:

SUMMARY STEPS

1. enable

2. configure terminal

3. dial-peer voice tag voip

4. vad [aggressive]

5. exit

6. voice vad-time milliseconds

7. voice-port slot/port

8. music-threshold number

9. comfort-noise

10. exit

DETAILED STEPS

 
Command
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 

dial-peer voice tag voip

Example:

Router(config)# dial-peer voice 555 voip

Enters dial-peer configuration mode.

Step 4 

vad [aggressive]

Example:

Router(config-dial-peer)# vad

Enables VAD for calls using this dial peer.

Note VAD is enabled by default. Use the vad command only if you have previously disabled the feature by using the no vad command.

Step 5 

exit

Example:

Router(config-dial-peer)# exit

Exits dial-peer configuration mode.

Step 6 

voice vad-time milliseconds

Example:

Router(config)# voice vad-time 500

Modifies the minimum silence detection time for VAD.

Step 7 

voice-port slot/port

Example:

Router(config)# voice-port 3/0

Enters voice-port configuration mode.

Note The syntax of this command is platform-specific. For information, refer to the Cisco IOS Voice Command Reference.

Step 8 

music-threshold number

Example:

Router(config-voiceport)# music-threshold -70

Specifies the minimal decibel level of music played when calls are put on hold. The decibel level affects how VAD treats the music data.

Valid values range from -70 to -30. If the music threshold is set too high and VAD is configured, the remote end hears no music; if the level is set too low, there is unnecessary voice traffic. Default is -38.

Step 9 

comfort-noise

Example:

Router(config-voiceport)# comfort-noise

Creates subtle background noise to fill silent gaps during calls when VAD is enabled on voice dial peers. If comfort noise is not generated, the resulting silence can fool the caller into thinking the call is disconnected instead of being merely idle.

Comfort noise is enabled by default.

Step 10 

exit

Example:

Router(config-voiceport)# exit

Exits voice-port configuration mode.


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