Table of Contents

Feature Overview

Benefits
Restrictions
Related Documents

Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks

Configuring Voice Ports to Detect Supervisory Disconnect Tones

Configuring a Voice Class for FXO Supervisory Disconnect Tone
Assigning an FXO Supervisory Disconnect Tone Voice Class to an FXO Voice Port

Configuring an FXO Voice Port to Disconnect with any Detected Tone
Verifying Configuration of Disconnect Tone Detection Parameters

Configuration Examples
Command Reference
cadence-list
cadence-max-off-time
cadence-min-on-time
cadence-variation
freq-max-delay
freq-max-deviation
freq-max-power
freq-min-power
freq-pair
freq-power-twist
supervisory disconnect anytone
supervisory disconnect dualtone voice-class
voice class dualtone
Glossary

FXO Supervisory Disconnect Tone

This feature module describes the FXO Supervisory Disconnect Tone feature for analog FXO ports with loop start signaling, introduced in Cisco IOS Release 12.1(3)T on the Cisco 2600 and 3600 series routers and Cisco MC3810 series concentrators.

This document includes the following sections:

• Feature Overview

• Supported Platforms

• Supported Standards, MIBs, and RFCs

• Prerequisites

• Configuration Tasks

• Configuration Examples

• Command Reference

• Glossary

Feature Overview

If the FXO Supervisory Disconnect Tone feature 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.

You can configure a voice port to detect either of the following tone types:

• Disconnect tones from the PBX or PSTN

  You can configure the FXO Supervisory Disconnect Tone feature to function in either of the following ways:

• Continuously throughout the call duration

• Before a call is answered

  As part of the tone detection process by the DSP, a DSP event is reported to the host software.

• Any tone received from the PBX or PSTN

  Detection of any tone is effective only during call set-up (before a call is answered), and echo cancellation must be enabled to prevent disconnection due to detection of the router's own ringback tone.

Benefits

The FXO Supervisory Disconnect Tone feature allows interoperability with PSTN and PBX systems whether or not they transmit supervisory tones.

Restrictions

The FXO Supervisory Disconnect Tone feature is applicable only to analog FXO ports with loop-start signaling.

The Cisco MC3810 series concentrators must be equipped with high-performance compression modules (HCMs) to support tone detection. Standard voice compression modules (VCMs) do not support the FXO Supervisory Disconnect Tone feature.

Related Documents

• Cisco IOS Multiservice Applications Configuration Guide, Cisco IOS Release 12.1

• Cisco IOS Multiservice Applications Command Reference, Cisco IOS Release 12.1

• Software Configuration Guide For Cisco 3600 Series and Cisco 2600 Series Routers

• Cisco MC3810 Multiservice Concentrator Configuration Guide

Supported Platforms

• Cisco 2600 series

• Cisco 3600 series

• Cisco MC3810 series

Supported Standards, MIBs, and RFCs

None

Prerequisites

The FXO Supervisory Disconnect Tone feature described in this document requires Cisco IOS Release 12.1(3)T or later.

Configuration Tasks

You can configure a voice port to disconnect when it detects a specific tone or tone pattern from a PBX or PSTN, or you can configure it to disconnect if it detects any tone before a call is answered.

For supervisory disconnect based on detection of a specific tone from a PBX or PSTN, complete the following tasks:

• Configuring Voice Ports to Detect Supervisory Disconnect Tones

• Verifying Configuration of Disconnect Tone Detection Parameters

For supervisory disconnect based on detection of any tone from a PBX or PSTN before a call is answered, complete the following tasks:

• Configuring an FXO Voice Port to Disconnect with any Detected Tone

• Verifying Configuration of Disconnect Tone Detection Parameters

Configuring Voice Ports to Detect Supervisory Disconnect Tones

To enable detection of supervisory disconnect tones, first create a voice class that defines the tone detection parameters, and then apply the voice class to the applicable analog FXO voice ports.

Configuring a Voice Class for FXO Supervisory Disconnect Tone

To configure a voice port to detect incoming tones, you need to know the parameters of the tones expected from the PBX or PSTN. 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 due to detection of non-supervisory tones or noise.

A supervisory disconnect tone is normally a dual tone consisting of two frequencies; however, tones of only one frequency can also be detected.

Caution If a voice port is configured to detect non-dual tones, unwanted disconnects can result from detection of random tone frequencies—the phenomenon of "talkoff."

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.

To create a voice class that defines the specific tone or tones to be detected, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# voice class dualtone tag	Create a voice class for defining one tone detection pattern. The range for the tag number is 1 to 10000. The tag number must be unique on the router.
Step 2	Router(config-voice-class)# freq-pair tone-id frequency-1 frequency-2	Specify the two frequencies in Hz for a tone to be detected (or one frequency if a non-dual tone is to be detected). If the tone to be detected contains only one frequency, enter 0 for frequency-2. Repeat this command for each additional tone to be specified. The tone-id range is 1 to 16. There is no default. The range for frequency-1 and frequency-2 is 300 to 3600, or you can enter 0 for frequency-2. There is no default.
Step 3	Router(config-voice-class)# freq-max-deviation frequency	Specify the maximum frequency deviation that will be detected, in Hz. The range is 10 to 125. The default is 10.
Step 4	Router(config-voice-class)# freq-max-power dBmO	Specify the maximum tone power that will be detected, in dBmO. The range is 0 to 20. The default is 10.
Step 5	Router(config-voice-class)# freq-min-power dBmO	Specify the minimum tone power that will be detected, in dBmO. The range is 10 to 35. The default is 30.
Step 6	Router(config-voice-class)# freq-power-twist dBmO	Specify the power difference allowed between the two frequencies, in dBmO. The range is 0 to 15. The default is 6.
Step 7	Router(config-voice-class)# freq-max-delay time	Specify the timing difference allowed between the two frequencies, in 10-millisecond increments. The range is 10 to 100 (100 ms to 1 s). The default is 20 (200 ms).
Step 8	Router(config-voice-class)# cadence-min-on-time time	Specify the minimum tone on time that will be detected, in 10-millisecond increments. The range is 0 to 100 (0 ms to 1 s).
Step 9	Router(config-voice-class)# cadence-max-off-time time	Specify the maximum tone off time that will be detected, in 10-millisecond increments. The range is 0 to 5000 (0 ms to 50 s).
Step 10	Router(config-voice-class)# 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	(Optional) Specify a tone cadence pattern to be detected. Specify an on time and off time for each cycle of the cadence pattern. The range for cadence-id is 1 to 10. There is no default. The range for the cycle on-time and off-time is 0 to 1000 (0 ms to 10 s). The default is 0.
Step 11	Router(config-voice-class)# cadence-variation time	(Optional) Specify the maximum time that the tone onset can vary from the specified onset time and still be detected, in 10-millisecond increments. The range is 0 to 200 (0 ms to 2 s). The default is 0.
Step 12	Router(config-voice-class)# exit	Exit from the voice-class configuration mode.

Assigning an FXO Supervisory Disconnect Tone Voice Class to an FXO Voice Port

To assign an FXO supervisory disconnect tone voice class to an analog FXO voice port, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	For Cisco 2600 and 3600 series analog voice ports: Router(config)# voice-port slot/subunit/port For Cisco MC3810 series analog voice ports: Router(config)# voice-port slot/port	Identify the voice port you want to configure and enter voice-port configuration mode.
Step 2	Router(config-voiceport)# supervisory disconnect dualtone {mid-call | pre-connect} voice-class tag	Assign an FXO supervisory disconnect tone voice class to the voice port. The voice class is one that you created in the "Configuring a Voice Class for FXO Supervisory Disconnect Tone" section. Specify mid-call for tone detection during the entire call. Specify pre-connect for tone detection only during call set-up.
Step 3	Router(config-voiceport)# exit	Exit from voice-port configuration mode.

Configuring an FXO Voice Port to Disconnect with any Detected Tone

To configure an analog FXO voice port to go on-hook upon receipt of any tone received from a PBX or PSTN before the call is answered, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	For Cisco 2600 and 3600 series analog voice ports: Router(config)# voice-port slot/subunit/port For Cisco MC3810 series analog voice ports: Router(config)# voice-port slot/port	Identify the voice port you want to configure and enter voice-port configuration mode.
Step 2	Router(config-voiceport)# supervisory disconnect anytone	Configure the voice port to disconnect on receipt of any tone.
Step 3	Router(config-voiceport)# exit	Exit from voice-port configuration mode.

Verifying Configuration of Disconnect Tone Detection Parameters

Use either or both of the following methods to verify that the tone detection parameters have been properly configured on a voice port:

Use the "show running-config" Command

Enter the show running-config command to review the tone detection parameters you have configured.

The following example shows part of the output from the show running-config command on a Cisco MC3810, in which voice class 70 defines the tone parameters:

:

router# show running-config
Building configuration...
.
.
.
voice class dualtone 70
 freq-max-deviation 20
 freq-max-power 6
 freq-min-power 25
 freq-power-twist 15
 freq-max-delay 16
 freq-pair 1 350 440
 freq-pair 2 500 800
 cadence-min-on-time 50
 cadence-max-off-time 200
 cadence-variation 5
.
.
.
voice-port 1/6 
 supervisory disconnect dualtone mid-call voice-class 70 
.
.
.

  Additional display lines are not shown.

Send a Supervisory Disconnect Tone from a PBX, the PSTN, or a SAGE Call Generator

Step 2   Use the PBX, PSTN, or SAGE to send a supervisory disconnect tone.

Note   The PBX or PSTN must be configured to send a supervisory disconnect tone when the call is terminated. The tone must match the the parameters you have configured in the router for supervisory disconnect. If you use a SAGE, the tone generated by the SAGE must match the parameters you have configured in the router for supervisory disconnect.

Step 3   On the router enter the show voice port summary command, and verify that the FXO port changes back to the on-hook state.

The following is a sample display from the show voice port summary command on a Cisco MC3810, in which analog FXO voice port 1/2 is on hook:

router# show voice port summary
                                IN       OUT
PORT   CH SIG-TYPE   ADMIN OPER STATUS   STATUS   EC
====== == ========== ===== ==== ======== ======== ==
1/2    -- fxo-ls     up    dorm idle     on-hook  y 
 

Configuration Examples

Creating a Voice Class to Specify FXO Supervisory Disconnect Tone Parameters

The following example configures voice class dualtone 70 with the following parameters:

• One tone, consisting of 350 Hz and 440 Hz, is specified for detection.

• No cadence list is defined; the cadence is defined by the cadence-min-on-time and cadence-max-off-time commands.

• The maximum detectable frequency deviation is 10 MHz.

• The maximum detectable tone power is 6 dBmO.

• The minimum detectable tone power is 25 dBmO.

• The detectable power difference between the two frequencies comprising the tone is 15 dBmO.

• The maximum detectable timing difference between the two frequencies comprising the tone is 160 ms.

• The cadence minimum on time is 500 ms.

• The cadence maximum off time is 4 seconds.

• The allowed cadence variation is 80 ms.

Router(config)# voice class 70
Router(config-voice-class)# freq-pair 1 350 440
Router(config-voice-class)# freq-max-deviation 10
Router(config-voice-class)# freq-max-power 6
Router(config-voice-class)# freq-min-power 25
Router(config-voice-class)# freq-power-twist 15
Router(config-voice-class)# freq-max-delay 16
Router(config-voice-class)# cadence-min-on-time 50
Router(config-voice-class)# cadence-max-off-time 400
Router(config-voice-class)# cadence-variation 8
Router(config-voice-class)# exit
 

The following example configures voice class dualtone 80 with the following parameters:

• One tone, consisting of 350 Hz and 440 Hz, is specified for detection.

• The maximum detectable frequency deviation is 10 MHz.

• The maximum detectable tone power is 6 dBmO.

• The minimum detectable tone power is 25 dBmO.

• The detectable power difference between the two frequencies comprising the tone is 15 dBmO.

• The maximum detectable timing difference between the two frequencies comprising the tone is 160 ms.

• The cadence minimum on time is 500 ms.

• The cadence maximum off time is 4 seconds.

• A cadence list defines on and off times to be detected: 1 s on, 1 s off, 3 s on, 3 s off.

• The allowed cadence variation is 80 ms.

Router(config)# voice class 80
Router(config-voice-class)# freq-pair 1 350 440
Router(config-voice-class)# freq-max-deviation 10
Router(config-voice-class)# freq-max-power 6
Router(config-voice-class)# freq-min-power 25
Router(config-voice-class)# freq-power-twist 15
Router(config-voice-class)# freq-max-delay 16
Router(config-voice-class)# cadence-min-on-time 50
Router(config-voice-class)# cadence-max-off-time 400
Router(config-voice-class)# cadence-list 1 100 100 300 300
Router(config-voice-class)# cadence-variation 8
Router(config-voice-class)# exit
 

The following example configures voice class dualtone 90 with the following parameters:

• Three tones are specified for detection. One consists of 350 Hz and 440 Hz, one consists of 480 Hz and 850 Hz, and one consists of 1000 Hz and 1250 Hz.

• The maximum detectable frequency deviation is 10 MHz.

• The maximum detectable tone power is 6 dBmO.

• The minimum detectable tone power is 25 dBmO.

• The detectable power difference between the two frequencies comprising each tone is 15 dBmO.

• The maximum detectable timing difference between the two frequencies comprising each tone is 160 ms.

• The cadence minimum on time is 500 ms.

• The cadence maximum off time is 5 seconds.

• Two cadence lists define on and off times to be detected:

  • Cadence list 1: 1 s on, 1 s off, 3 s on, 3 s off, 1 s on, 2 s off

  • Cadence list 2: 1 s on, 2 s off, 1 s on, 4 s off

• The allowed cadence variation is 80 ms.

Router(config)# voice class 90
Router(config-voice-class)# freq-pair 1 350 440
Router(config-voice-class)# freq-pair 2 480 850
Router(config-voice-class)# freq-pair 3 1000 1250
Router(config-voice-class)# freq-max-deviation 10
Router(config-voice-class)# freq-max-power 6
Router(config-voice-class)# freq-min-power 25
Router(config-voice-class)# freq-power-twist 15
Router(config-voice-class)# freq-max-delay 16
Router(config-voice-class)# cadence-min-on-time 50 
Router(config-voice-class)# cadence-max-off-time 500
Router(config-voice-class)# cadence-list 1 100 100 300 300 100 200
Router(config-voice-class)# cadence-list 2 100 200 100 400
Router(config-voice-class)# cadence-variation 8
Router(config-voice-class)# exit
 

Applying a Voice Class to a Voice Port

This example applies voice class 70 to FXO voice port 1/2 on a Cisco MC3810, and specifies tone detection for the entire duration of the call.

Router(config)# voice port 1/1
Router(config-voiceport)# no echo-cancel enable
Router(config-voiceport)# connection plar 12
Router(config-voiceport)# supervisory disconnect dualtone mid-call voice-class 70
Router(config-voiceport)# exit

This example applies voice class 80 to FXO voice port 0/1/0 on a Cisco 3600 series router, and specifies tone detection for the call set-up time only.

Router(config)# voice port 0/1/0
Router(config-voiceport)# no echo-cancel enable
Router(config-voiceport)# connection plar 12
Router(config-voiceport)# supervisory disconnect dualtone pre-connect voice-class 80
Router(config-voiceport)# exit

Configuring a Voice Port to Disconnect with Any Detected Tone

This example configures voice port 1/1 to go on-hook upon receipt of any tone from a PBX or PSTN if the caller goes on-hook before the call is answered:

Router(config)# voice port 1/1
Router(config-voiceport)# echo-cancel enable
Router(config-voiceport)# connection plar 12
Router(config-voiceport)# supervisory disconnect anytone
Router(config-voiceport)# exit

Command Reference

This section documents new commands. All other commands used on these platforms are documented in the Cisco IOS Release 12.1 command reference publications.

• cadence-list

• cadence-max-off-time

• cadence-min-on-time

• cadence-variation

• freq-max-delay

• freq-max-deviation

• freq-max-power

• freq-min-power

• freq-pair

• freq-power-twist

• supervisory disconnect anytone

• supervisory disconnect dualtone voice-class

• voice class dualtone

cadence-list

To specify a tone cadence pattern to be detected, use the cadence-list voice-class command. To delete a cadence pattern, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# cadence-list 1 100 100 300 300 100 200

Router(config-voice-class)# cadence-list 2 100 200 100 400

Router(config-voice-class)# exit

cadence-max-off-time

To specify the maximum off duration for detection of a tone, use the cadence-max-off-time voice-class command. To restore the default, use the no form of this command.

Router(config)# voice class dualtone 100

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

Router(config-voice-class)# exit

cadence-min-on-time

To specify the minimum on duration for detection of a tone, use the cadence-min-on-time voice-class command. To restore the default, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# cadence-min-on-time 3

Router(config-voice-class)# exit

cadence-variation

To specify the cadence variation time allowed for detection of a tone, use the cadence-variation voice-class command. To restore the default cadence variation time, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# cadence-variation 3

Router(config-voice-class)# exit

Router(config)#

freq-max-delay

To specify the maximum timing difference allowed between the two frequencies for detection of a tone, use the freq-max-delay voice-class command. To restore the default allowed timing difference, use the no form of this command.

Router(config)# voice class dualtone 100

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

Router(config-voice-class)# exit

freq-max-deviation

To specify the maximum frequency deviation allowed in a tone, use the freq-max-deviation voice-class command. To restore the default maximum frequency deviation, use the no form of this command.

Router(config)# voice class dualtone 100

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

Router(config-voice-class)# exit

freq-max-power

To specify the upper limit of the tone power allowed in a tone, use the freq-max-power voice-class command. To restore the default maximum tone power, use the no form of this command.

Router(config)# voice class dualtone 100

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

Router(config-voice-class)# exit

freq-min-power

To specify the lower limit of the tone power allowed in a tone, use the freq-min-power voice-class command. To restore the default minimum tone power, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# freq-min-pwr 15

Router(config-voice-class)# exit

freq-pair

To specify the frequency components of a tone to be detected, use the freq-pair voice-class command. To cancel detection of a tone, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# freq-pair 1 480 2400

Router(config-voice-class)# exit

 

Router(config)# voice class dualtone 50

Router(config-voice-class)# freq-pair 1 480 2400

Router(config-voice-class)# freq-pair 2 560 880

Router(config-voice-class)# exit

 

freq-power-twist

To specify the power difference allowed between the two frequencies of a tone, use the freq-power-twist voice-class command. To restore the default power difference allowed, use the no form of this command.

Router(config)# voice class dualtone 100

Router(config-voice-class)# freq-power-twist 3

Router(config-voice-class)# exit

supervisory disconnect anytone

To configure an FXO voice port to go on-hook if the router detects any tone from a PBX or PSTN before the call is answered, use the supervisory disconnect anytone voice-port command. To restore the default, use the no form of this command.

Router(config)# voice-port 1/4

Router(config-voice-class)# supervisory disconnect anytone

Router(config-voice-class)# exit

Router(config)# voice-port 1/5

Router(config-voice-class)# supervisory disconnect anytone

Router(config-voice-class)# exit

 

Router(config)# voice-port 1/5

Router(config-voice-class)# no supervisory disconnect anytone

Router(config-voice-class)# exit

 

supervisory disconnect dualtone voice-class

To assign a previously-configured voice class for FXO supervisory disconnect tone to a voice port, use the supervisory disconnect dualtone voice-class voice port configuration command. To remove a voice class from a voice port, use the no form of this command.

Router(config)# voice-port 1/5

Router(config)# no echo-cancel enable

Router(config-voiceport)# supervisory disconnect dualtone mid-call voice-class 70

Router(config-voiceport)# exit

 

Router(config)# voice-port 0/1/1

Router(config)# no echo-cancel enable

Router(config-voiceport)# supervisory disconnect dualtone pre-connect voice-class 80

Router(config-voiceport)# exit

 

voice class dualtone

To create a voice class for FXO supervisory disconnect tone detection parameters, use the voice class dualtone global configuration command. To delete the voice class, use the no form of this command.

Router(config)# voice class dualtone 70

Router(config-voice-class)# freq-pair 1 350 440

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

Router(config-voice-class)# freq-max-power 6

Router(config-voice-class)# freq-min-power 25

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

Router(config-voice-class)# freq-max-delay 16

Router(config-voice-class)# cadence-min-on-time 50

Router(config-voice-class)# cadence-max-off-time 400

Router(config-voice-class)# cadence-variation 8

Router(config-voice-class)# exit

 

Router(config)# voice class dualtone 70

Router(config-voice-class)# freq-pair 1 350 440

Router(config-voice-class)# freq-pair 2 480 850

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

Router(config-voice-class)# freq-max-power 6

Router(config-voice-class)# freq-min-power 25

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

Router(config-voice-class)# freq-max-delay 16

Router(config-voice-class)# cadence-min-on-time 50

Router(config-voice-class)# cadence-max-off-time 400

Router(config-voice-class)# cadence-list 1 100 100 300 300

Router(config-voice-class)# cadence-variation 8

Router(config-voice-class)# exit

 

Router(config)# voice class dualtone 90

Router(config-voice-class)# freq-pair 1 350 440

Router(config-voice-class)# freq-pair 2 480 850

Router(config-voice-class)# freq-pair 3 1000 1250

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

Router(config-voice-class)# freq-max-power 6

Router(config-voice-class)# freq-min-power 25

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

Router(config-voice-class)# freq-max-delay 16

Router(config-voice-class)# cadence-min-on-time 50

Router(config-voice-class)# cadence-max-off-time 500

Router(config-voice-class)# cadence-list 1 100 100 300 300 100 200

Router(config-voice-class)# cadence-list 2 100 200 100 400

Router(config-voice-class)# cadence-variation 8

Router(config-voice-class)# exit

 

Glossary

ABCD signaling—Four-bit telephony line signaling coding in which each letter of "ABCD" represents one of the four bits. This is often associated with CAS or Robbed-Bit signaling on a T1 or E1 telephony trunk.

AIS—Alarm Indication Signal.

AVBO—Advanced Voice Busy Out.

Cisco trunk (private line) call—A Cisco trunk (private line) call is established by the forced connection of a dynamic switched call. A Cisco trunk call is established during configuration of the trunk and stays up for the duration of the configuration. Optionally, it provides a pass-through connection path to pass signaling information between the two telephony interfaces at either end of the connection.

CLI—Command line interface.

codec—coder-decoder. An integrated circuit device that typically uses pulse code modulation to transform analog signals into a digital bit stream, and digital signals back into analog signals. In Voice over IP, Voice over Frame Relay, and Voice over ATM, a DSP software algorithm used to compress/decompress speech or audio signals.

DLCI—Data-link connection identifier.

Dial peer—An addressable call endpoint that contains configuration information including voice protocol, a CODEC type, and a telephone number associated with the call endpoint. There are five kinds of dial peers: POTS, VoIP, VoFR, VoATM, and VoHDLC.

DSP—Digital Signaling Processor.

DTMF—Dual tone multi frequency. Uses two simultaneous voice-band tones for dial such as touch tone.

DTMF relay—Enables the generation of FRF.11 Annex A frames for a VoFR dial peer. The DSP generates Annex A frames instead of passing a DTMF tone through the network as a voice sample.

Dynamic switched call—A telephone call dynamically established across a packet data network based on a dialed telephone number. In the case of VoFR, a Cisco proprietary session protocol similar to Q.931 is used to achieve call switching and negotiation between calling endpoints. The proprietary session protocol runs over FRF.11-compliant subchannels.

E&M—Stands for 2-wire or 4-wire interfaces with separate signaling paths (from "Ear and Mouth," also "recEive and transMit"). E&M is a trunking arrangement generally used for two-way switch-to-switch or switch-to-network connections. The Cisco analog E&M interface is an RJ-48 connector that allows connections to PBX trunk lines (tie lines). E&M is also available on E1 and T1 digital interfaces.

E1—European equivalent of T1. 32-64kbps channels include 1-channel for framing and 1-channel for D-channel information. The clock rate is 2.048 Mhz.

FRF—Frame Relay Forum. An association of corporate members consisting of vendors, carriers, users, and consultants committed to implementing Frame Relay in accordance with national and international standards. See http://www.frforum.com.

FRF.11—Frame Relay Forum implementation agreement for Voice over Frame Relay (v1.0 May 1997). This specification defines multiplexed data, voice, fax, DTMF digit-relay, and CAS/Robbed-bit signaling frame formats, but does not include call setup, routing, or administration facilities. See http://www.frforum.com.

FRF.11 Annex C—See FRF.12.

FRF11-trunk—A point-to-point permanent voice connection (private line) conforming to the FRF.11 specification.

FRF.12—The FRF.12 Implementation Agreement (also known as FRF.11 Annex C) was developed to allow long data frames to be fragmented into small pieces and interleaved with real-time frames. In this way, real-time voice and non real-time data frames can be carried together on low speed links without causing excessive delay to the real-time traffic.

FXO—Foreign Exchange Office. An FXO interface connects to the Public Switched Telephone Network (PSTN) central office and is the interface offered on a standard telephone. The Cisco FXO interface is an RJ-11 connector that allows an analog connection to be directed to the PSTN central office or to a station interface on a PBX.

FXS—Foreign Exchange Station. An FXS interface connects directly to a standard telephone and supplies ring, voltage, and dial tone. The Cisco FXS interface is an RJ-11 connector that allows connections to basic telephone service equipment, keysets, and PBXs.

ICPIF—Calculated Planning Impairment Factor.

LVBO—Local Voice Busy Out.

MEL CAS—Mercury Exchange Limited (MEL) Channel Associated Signaling (CAS). A voice signaling protocol used primarily in the United Kingdom.

OOS—Out of Service state of the call or trunk.

PBX—Private Branch Exchange. A privately owned central switching office.

Permanent calls—Permanent calls are private line calls used for fixed point-to-point calls, connections between PBXs (E&M to E&M), or for remote telephone extensions (FXO to FXS).

POTS—Plain old telephone service. Basic telephone service supplying standard single line telephones, telephone lines, and access to the PSTN.

POTS dial peer—Dial peer connected by a traditional telephony network. POTS peers point to a particular voice port on a voice network device.

PSTN—Public Switched Telephone Network. PSTN refers to the local telephone company.

RTR—Response Time Reporter.

Switched calls—Switched calls are normal telephone calls when a user picks up a phone, hears a dial tone, and enters the destination phone number to reach the other phone. Switched calls can also be private line auto-ringdown (PLAR) calls, or tie-line calls for fixed point-to-point connections.

T1—Digital WAN carrier facility. T1 transmits DS-1-formatted data at 1.544 Mbps through the telephone-switching network by using AMI or B8ZS coding.

Tandem switching—The dynamic switching of voice calls between VoFR, VoATM, or VoHDLC PVCs and subchannels; also called tandeming. Tandem switching is often encountered in multi-hop VoFR call connection paths.

Trunk—Service that allows quasi-transparent connections between two PBXs, a PBX and a local extension, or some other combination of telephony interfaces with signaling passed transparently through the packet data network.

VoFR—Voice over Frame Relay.

VoFR dial peer—Dial peer connected by a Frame Relay network. VoFR peers point to specific VoFR devices.

Voice over Frame Relay—Voice over Frame Relay enables a router to carry voice traffic, for example, telephone calls and faxes, over a Frame Relay network. When sending voice traffic over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network by using FRF.12 encapsulation.

Voice over IP—Voice over IP enables a router to carry voice traffic, for example, telephone calls and faxes, over an IP network. In Voice over IP, the DSP segments the voice signal into frames, which are then coupled in groups of two and stored in voice packets that are transported by using IP in compliance with ITU-T specification H.323.

VoIP—Voice over IP through Ethernet.

Posted: Wed Sep 27 12:49:16 PDT 2000
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