Avaya Experience Portal Documentation Library

Change TTS Server page field descriptions

Last Updated : Jun 05, 2026 |

Use this page to change an existing Text-to-Speech (TTS) server.

For all TTS changes except for Enable/Disable, after you save the changes, the System Monitor web page and the MPP Manager web page on EPM display the Restart needed configuration status for affected MPPs that are in the Running state. You must restart the affected MPPs before the applications can use the modified configuration.

This page contains the:

General Section


Field	Description
Zone	The name of the zone where the TTS server is configured. Select the name of the zone from the drop-down box. Note: The Zone drop-down box appears only if you have created zones on your Experience Portal system. If you do not create any new zones, you do not see the drop-down box.
Name	The unique identifier for this TTS server on the Experience Portal system. If you are using a Nuance server, this name must be between 1 and 32 characters. Note: You cannot change this name once you save the TTS server.
Enable	Whether this TTS server is available for use by the Experience Portal system. The default is Yes, which means the server is available. Note: When you change this value from Yes to No, no new calls will use this server. However, any calls in progress may continue to use the speech server. You must let the ongoing calls to complete before taking the speech server out of service to avoid application errors.
Engine Type	The type of TTS software engine the server uses. The options are: Loquendo Nuance The selection of an engine type in this field affects what the EPM displays as the defaults in the Base Port, New Connection per Session, Voices and RTSP URL fields as well. Note: Once you save the TTS server, this engine type cannot be changed. Note: To add a third-party TTS server type that mimics an existing TTS server, see Adding a third-party TTS Server type.
Network Address	The network address, or location, of the TTS server you want to use. This must be a valid network address in the form of a fully qualified hostname or an IP address. When you enter a network address in this field, the EPM automatically inserts the address as part of the RTSP URL field.
Base Port	The port number on the TTS server to which requests for TTS services are to be sent. The value for this field depends on the selected engine type and the MRCP protocol: For Loquendo, the default is 554 For Nuance, the default is port 4900 The default port value changes to 5060 if you select MRCPV2 (TCP) protocol and to 5061 for MRCPV2 (TLS) protocol. Important: These values are set to the default port numbers on the respective TTS servers. Unless you have manually changed the default settings on the TTS server, you should not have to change them here.
Total Number of Licensed TTS Resources	The total number of licensed TTS resources that is used by the Experience Portal system. Experience Portal uses this information to determine the total number of TTS resources available to the Experience Portal system.
New Connection per Session	Whether Experience Portal establishes a new connection on the TTS server for each call session. If you are using: Loquendo, set this to Yes Nuance, set this to No Important: You must use the above settings for this parameter.
Voices	Displays all voices that TTS servers can use on this system. Select an individual entry in this list by clicking on it, or use `Ctrl+Click` and `Shift+Click` to select multiple entries. Then, click the button to move the selected voices to the Selected Voices field. To move the voices back from the Selected Voices field to the Voices field, click on the button. This list of voices in the Voices field is prepopulated with the list of the voices that were available for the designated TTS engine type when Experience Portal was released. It is maintained in a special file on the Experience Portal system and is not automatically updated. You must verify that the voices you select here are actually installed and available on the target TTS server. You can add more voices to this list by clicking Configuration>Speech Servers from the EPM menu and selecting Customize in the TTS tab. Note: If a speech application is configured to use more language/voice combinations than are configured for any single TTS server, Experience Portal sends a `No TTS Resource` exception to the application. What happens then depends on the event handler that the application uses.
Selected Voices	All voices that you select in the Voices pane appear in this pane.
Listed Directory Number (LDN)	This field is only shown when you are logged into the EPM using the Avaya Services init account created when the Avaya Service accounts were configured. If you are logged into the EPM using the init account, enter the LDN number for this server as it appears in the Avaya Services database. If an LDN number is not specified for this server, Experience Portal uses the default value (000)000-0000.

MRCP Section


Field	Description
Ping Interval	When a speech application requires TTS rendering, the MPP establishes a connection to the TTS server at the beginning of a session. Because there is no way to know when the connection will be used during the session, Experience Portal sends periodic "heartbeat" messages to the TTS server to make sure the connection is not terminated prematurely. This field specifies the number of seconds the Experience Portal system waits between the heartbeat messages. Enter an integer in this field. The default is 15. Note: The value specified in this field does not affect TTS timeout.
Response Timeout	An integer value specifying the number of seconds to wait for the TTS server to respond to a request for TTS before timing out. The default is 4.
Protocol	The MRCP protocol used for allocating the media processing server resources (TTS). The options are: MRCP V1 MRCP V2 — MRCPv2 option is shown only when you select Nuance in the Engine Type field. Note: If you have installed Avaya Aura® Media Server on the system, the only option available is MRCP V1. The default is MRCP V1.
RTSP URL	The URL of the Real-Time Streaming Protocol (RTSP) server. The RTSP server is the network remote control for the Experience Portal multimedia servers. The default path depends on which TTS engine type you select in the Engine Type field. If you change the Engine Type, this field also changes to a new default. To change the default path, first select the TTS engine type and then overwrite the default value in this field.
Enable Session XML	Displays when you select the MRCP V2 option in the Protocol field. Parameters specified in the session.xml file supersede vendor-specific parameters specified on the Applications webpage. The options are: Yes: Session.xml specified for each voice application is sent to the speech server. If Session.xml is not specified for the voice application, the system generates and sends a session.xml file that consists of an organization and application name. No: Session.xml is not sent to the speech server for any voice application.
Transport Protocol	This field is only shown when you select the MRCP V2 protocol under the MRCP section. The transport protocol used for transporting the real-time data. The options are: TCP TLS The default is TCP. The TLS option is shown only when you select Nuance in the Engine Type field. Important: If you select TLS, ensure that the CA certificate that signed the identity certificate of the speech server is installed on Experience Portal as a trusted certificate. On the EPM navigation pane, click Security > Certificates > Trusted Certificates. Ensure that the required trusted certificate of the speech server is installed. If it is not uploaded, upload the certificate. Click System Maintenance > Log Viewer to check for speech server connection errors.
Listener Port	This field is only shown when you select the MRCP V2 protocol under the MRCP section. Enter an integer value in the range 1 – 65535. The default is 5060 if you select MRCPV2 (TCP) protocol and 5061 for MRCPV2 (TLS) protocol.

SRTP Section

Note:

This group only appears if the Transport Protocol field is set to TLS.


Field	Description
Enable	The options are: Yes : This connection uses SRTP. No : This connection does not use SRTP.
Encryption Algorithm	The options are: AES_CM_128: This connection uses 128 key encryption. None: Messages sent through this connection are not encrypted.
Authentication Algorithm	The options are: HMAC_SHA1_80: Authentication is done with HMAC SHA-1 which uses 80 bit key for the authentication. HMAC_SHA1_32: Authentication is done with HMAC SHA-1 which uses 32 bit key for the authentication.
RTCP Encryption Enabled	The options are: Yes : This connection uses RTP Control Protocol encryption. No : This connection does not use RTP Control Protocol encryption.
RTP Authentication Enabled	The options are: Yes : This connection uses Real-time Transport Protocol authentication. No : This connection does not use Real-time Transport Protocol authentication.
Add	Adds the SRTP configuration to the Configured SRTP List.

Configured SRTP List group

This group displays any SRTP configurations defined for the connection.