# Setting up prompts and music on hold in Webex Contact Center For Webex Contact Center administrators and flow developers configuring voice prompts and queue music. Canonical: https://warmtransfer.net/guides/wxcc-audio-prompts-setup Last verified: 2026-09-30 Webex Contact Center plays prompts and queue music using uploaded audio files and built-in or integrated text-to-speech[^36][^30]. Each queue has a Default music in queue field naming the.wav file played when calls arrive or wait in the queue[^30]. ## Before you start - Confirm that the voice media platform is active; the Next Generation Voice Media Platform is the default for new trials and subscriptions during activation[^46]. - Ensure any audio files intended for prompts or queue music are available locally for conversion and upload[^45]. - Flow Designer enforces self-loop limits per activity, including 100 for Queue Contact[^47]. ## What changes by situation - Where do spoken prompts originate? Recorded prompts: upload WAV audio files; Text-to-speech: platform synthesizes text. - How many languages do callers hear? Single prompt set: all callers hear the same language; Per-language sets: caller language selection determines prompts. ## Step 1: Open the Audio files page in Control Hub ### Do In Control Hub, navigate to Services > Contact Center > Customer Experience > Audio files[^5]. ### Verify The Audio files page displays and shows a Create Audio file button[^13]. ### Rollback Suggested rollback: navigate back to the overview page. ## Step 2: Prepare the audio files **Recorded prompts: upload WAV audio files** ### Do Convert all prompt recordings and music files to WAV format, mono audio, with an 8 kHz sample rate and 8-bit u-law encoding[^45]. Assign unique file names before uploading, because bulk imports replace existing files that share the same file name[^9]. ### Verify Suggested check: inspect the properties of each file in an audio editor or utility to verify the format against the required audio specification. ### Rollback Suggested rollback: remove converted files from the local working directory. **Text-to-speech: platform synthesizes text** ### Do Convert music files to WAV format, mono audio, with an 8 kHz sample rate and 8-bit u-law encoding[^45]. Spoken prompts do not require local WAV conversion because Webex Contact Center converts written text into synthesized audio for IVR[^36]. ### Verify Suggested check: inspect the properties of each music file in an audio editor or utility to verify the format against the required audio specification. ### Rollback Suggested rollback: remove converted files from the local working directory. ## Step 3: Upload audio files ### Do For individual files, click Create Audio file on the Audio files page, provide a description, select the file, and save; the Name field populates automatically[^13]. For larger sets, place the files in a folder structure and create a ZIP archive[^11]. In Control Hub, navigate to Services > Contact Center > Tenant Settings > Bulk Operations to import the archive[^8]. Bulk Operations accepts only WAV files, scans folders recursively, and requires archives to remain at or below 50 MB per request[^11][^10]. Alternatively, use the Audio Files API multipart upload endpoint with an administrator token carrying the cjp:config scope and set contentType to AUDIO_WAV or AUDIO_X_WAV[^2][^3]. Note that updating an audio file currently in use is not supported[^22], and the API's List References operation can be used to identify which flow variables are tied to a file[^4]. ### Verify Open Services > Contact Center > Customer Experience > Audio files and confirm the uploaded files appear in the list[^5]. ### Rollback Delete individual files by selecting the prompt and clicking the delete icon at the top right[^14]. Maintain local copies of all files, as Bulk Operations does not support exporting audio files[^7]. ## Step 4: Configure text-to-speech connectors and variables **Recorded prompts: upload WAV audio files** ### Do An existing audio prompt is changed by opening it on the Audio files page, replacing the existing file and clicking Save[^15]. ### Verify Suggested check: verify that all required recorded prompts are visible on the Audio files page before configuring flow activities. ### Rollback Suggested rollback: no changes to reverse. **Text-to-speech: platform synthesizes text** ### Do In Flow Designer, configure the global variables Global_VoiceName and Global_Language in the flow; Cisco Text-to-Speech requires both variables to set the default language and voice[^40]. Cisco TTS provides 22 languages with two voices per language (one male and one female)[^35]. If Google voices are required, enable the Cloud Text-to-Speech API in Google Cloud Platform Console and download an authentication key JSON file[^19]. In Control Hub, go to Services > Contact Center > Tenant Settings > Integrations > Connectors, select the Google card, assign a unique name, and upload the authentication key[^20]. An organization supports up to 10 Google connectors[^18]. When building subflows, note that a 2024 Cisco TAC tech note indicates Global_Language and Global_VoiceName are not available inside a subflow; create two local variables with those exact names and populate them using Set Variable activities before TTS prompts[^32][^33]. ### Verify In Flow Designer, open the Prompt settings of an IVR activity (such as Play Message, Menu, or Collect Digits) on a Next Generation Voice Media Platform tenant and verify that Cisco TTS and Google TTS connector options appear[^37]. ### Rollback Delete the Global_VoiceName and Global_Language variables from the flow, and remove any added Google connectors under Services > Contact Center > Tenant Settings > Integrations > Connectors[^20][^40]. ## Step 5: Configure language selection **Single prompt set: all callers hear the same language + Recorded prompts: upload WAV audio files** ### Do An existing audio prompt is changed by opening it on the Audio files page, replacing the existing file and clicking Save[^15]. ### Verify Suggested check: confirm in Flow Designer that prompt activities reference default files. ### Rollback Suggested rollback: no configuration to revert. **Per-language sets: caller language selection determines prompts + Recorded prompts: upload WAV audio files** ### Do An existing audio prompt is changed by opening it on the Audio files page, replacing the existing file and clicking Save[^15]. ### Verify Place a test call, select each language option, and verify that the corresponding audio prompt plays[^34]. ### Rollback Suggested rollback: replace variable prompts with a single static audio file. **Single prompt set: all callers hear the same language + Text-to-speech: platform synthesizes text** ### Do To use the default language and voice for Cisco Text-to-Speech, the flow must have the global variables Global_VoiceName and Global_Language configured[^40]. ### Verify Suggested check: confirm in Flow Designer that prompt activities reference global default voice settings. ### Rollback Suggested rollback: no configuration to revert. **Per-language sets: caller language selection determines prompts + Text-to-speech: platform synthesizes text** ### Do In the flow, the default Cisco TTS language and voice are overridden by a Set Variable activity carrying the appropriate voice name code[^41]. This overrides the default voice configured by Global_VoiceName and Global_Language[^40][^41]. ### Verify Place a test call into the flow, select each language option, and verify that synthesis uses the selected language and voice[^34]. ### Rollback Remove the Set Variable activities that override the voice codes so the flow reverts to Global_VoiceName and Global_Language[^40][^41]. ## Step 6: Build greetings with Play Message **Recorded prompts: upload WAV audio files** ### Do An existing audio prompt is changed by opening it on the Audio files page, replacing the existing file and clicking Save[^15]. ### Verify Suggested check: confirm that the configured prompt audio plays back as expected. ### Rollback Suggested rollback: remove the selected audio files from the prompt configuration. **Text-to-speech: platform synthesizes text** ### Do Flow Designer media activities such as Play Message, Collect Digits and Menu support dynamic text-to-speech, where expressions embed custom data in the utterance and SSML adjusts how it is spoken[^38]. Cisco TTS accepts the SSML tags speak, break, say-as, audio, p, s, prosody and sub[^42]. Note that a text-to-speech message of more than one line requires a Pebble escape filter for the system to play it[^48], and Cisco instructs that single quotes be used instead of double quotes inside an expression[^49]. ### Verify Suggested check: preview or test the synthesized utterance in Flow Designer. ### Rollback Suggested rollback: clear the dynamic text-to-speech utterance from the activity. ## Step 7: Configure default queue music ### Do Each queue has a Default music in queue field naming the.wav file played when calls arrive or wait in the queue, and that file is played if Play Music is not configured in the Queue Contact activity[^30]. ### Verify Inspect the queue configuration in Control Hub to confirm that Default music in queue displays the selected WAV file[^30]. ### Rollback Suggested rollback: open the queue settings and select the previous audio file in the Default music in queue field. ## Step 8: Build the in-queue treatment loop ### Do After Queue Contact or Queue To Agent, flow execution continues with the attached activities, and pre-configured music is played to the waiting customer by attaching a Play Music activity[^29]. Flow Designer enforces self-loop limits per activity, including 100 for Queue Contact[^47]. Optionally, add a Get Queue Info activity to fetch position in queue (PIQ) and estimated wait time (EWT)[^17], and speak these values using text-to-speech expressions[^38]. ### Verify Place a test call while ensuring no agents are available, and listen to verify that music plays and transitions to queue treatment[^34]. ### Rollback Suggested rollback: disconnect the loop connections in Flow Designer and remove the Play Music activity; calls waiting in queue will fall back to the Default music in queue file[^30]. ## Step 9: Configure outdial entry point music on hold ### Do Telephony channels are created and edited in Control Hub under Services > Contact Center > Customer Experience > Channels, and Music on Hold is one of the Entry Point Settings fields there[^12]. The channel's Music on Hold field is described as the music file to use in the Outdial Entry Point[^23]. ### Verify Open the outbound channel settings under Services > Contact Center > Customer Experience > Channels and confirm that the Music on Hold field displays the selected file[^12]. ### Rollback Suggested rollback: open the outbound channel settings and revert Music on Hold to the previously assigned file or clear the field. ## Step 10: Publish and test ### Do Flow Designer has no version control feature[^50]. The flow version number counts how many times the flow has been published, and version labels can be applied[^50]. ### Verify Place a call into the flow and listen for the expected language and voice name[^34]. ### Rollback Suggested rollback: re-import or republish a previously saved version of the flow. ## Applicability Applies to: Cisco Webex Contact Center. Deployments: multi-tenant. Sources checked 2026-09-30. ## What remains uncertain - Whether an audio file currently in use can be successfully overwritten using a same-named bulk import is not covered by the sources below. - Whether subflows still fail to inherit the global variables Global_Language and Global_VoiceName in current releases beyond late 2024 is not covered by the sources below. - The exact voice name codes for languages other than en-US are not covered by the sources below. - The specific runtime conditions under which the Outdial Entry Point Music on Hold setting plays to connected parties are not covered by the sources below. ## Sources [^1]: The 2021 Setup and Administration Guide describes a setting that selects the .wav file played to the caller when an agent puts a call on hold. Source: [Cisco Webex Contact Center Setup and Administration Guide - Contact Routing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/webexcc/SetupandAdministrationGuide_2/b_mp-release-2/b_cc-release-2_chapter_0100.html), Contact Routing chapter, music on hold field description. Checked 2026-09-30. [^2]: An Audio Files API upload is multipart form data with a JSON audioFileInfo part, whose contentType is AUDIO_WAV or AUDIO_X_WAV, and a binary audioFile part. Source: [The A-Z of Webex Contact Center APIs: Audio Files](https://developer.webex.com/blog/the-a-z-of-webex-contact-center-apis-audio-files), Create a New Audio File section. Checked 2026-09-30. [^3]: The Audio Files API offers create, update, partial update, get, delete, list and list-references operations, and creating a file needs an administrator access token with the cjp:config scope. Source: [The A-Z of Webex Contact Center APIs: Audio Files](https://developer.webex.com/blog/the-a-z-of-webex-contact-center-apis-audio-files), endpoint list and Create a New Audio File section. Checked 2026-09-30. [^4]: The Audio Files API's List References operation shows which variables in which flows are tied to a given audio file. Source: [The A-Z of Webex Contact Center APIs: Audio Files](https://developer.webex.com/blog/the-a-z-of-webex-contact-center-apis-audio-files), List References For a Specific Audio File section. Checked 2026-09-30. [^5]: Audio prompts are managed in Control Hub under Services > Contact Center > Customer Experience > Audio files. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, procedure steps 1-3. Checked 2026-09-30. [^6]: One IVR flow can serve several languages: an audio prompt variable configured in Play Music, Play Message, Menu or Collect Digits selects the audio prompt dynamically for the language the customer chose. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), audio prompt variable passages in the Play Message, Play Music, Menu and Collect Digits sections. Checked 2026-09-30. [^7]: Bulk Operations does not support exporting audio files. Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), Audio files section. Checked 2026-09-30. [^8]: Bulk Operations is opened in Control Hub under Services > Contact Center > Tenant Settings > Bulk Operations. Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), procedure, navigation steps. Checked 2026-09-30. [^9]: When a bulk import contains an audio file whose file name already exists in the tenant, the new file replaces the old one. Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), Audio files section. Checked 2026-09-30. [^10]: The maximum ZIP size for a bulk audio import is 50 MB; larger sets must be split into several requests of at most 50 MB each. Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), Audio files section. Checked 2026-09-30. [^11]: Bulk Operations imports audio files from a ZIP archive, accepts only WAV files, and walks the archive's folders recursively to import each .wav file. Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), Audio files section. Checked 2026-09-30. [^12]: Telephony channels are created and edited in Control Hub under Services > Contact Center > Customer Experience > Channels, and Music on Hold is one of the Entry Point Settings fields there. Source: [Set up voice channels for Webex Contact Center](https://help.webex.com/en-us/article/2dputx/Set-up-voice-channels-for-Webex-Contact-Center), channel creation procedure, Entry Point Settings step. Checked 2026-09-30. [^13]: To add an audio prompt, the administrator clicks Create Audio file on the Audio files page, gives a description, uploads the audio file and saves; the Name field is filled in automatically. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, create procedure. Checked 2026-09-30. [^14]: An audio prompt is removed with the delete icon at the top right of its page in Control Hub. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, delete procedure. Checked 2026-09-30. [^15]: An existing audio prompt is changed by opening it on the Audio files page, replacing the existing file and clicking Save. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, edit procedure. Checked 2026-09-30. [^16]: A prompt in an IVR activity can hold up to five audio prompts in total, counting audio files and audio prompt variables together. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Message and Collect Digits sections, Prompt settings. Checked 2026-09-30. [^17]: The Get Queue Info activity returns the contact's position in queue (PIQ) and the estimated wait time (EWT). Source: [Understand Routing and Queueing in Webex Contact Center](https://help.webex.com/en-us/article/np2fdx/Understand-Routing-and-Queueing-in-Webex-Contact-Center), Get Queue Info activity section. Checked 2026-09-30. [^18]: An organization can add up to ten Google connectors. Source: [Configure Google connector for Webex Contact Center](https://help.webex.com/en-us/article/ctge8i/Configure-Google-connector-for-Webex-Contact-Center), notes following the procedure. Checked 2026-09-30. [^19]: Before adding the Google connector, the administrator must download a Google Cloud authentication key (JSON file) and enable the Cloud Text-to-Speech API in the Google Cloud Platform Console. Source: [Configure Google connector for Webex Contact Center](https://help.webex.com/en-us/article/ctge8i/Configure-Google-connector-for-Webex-Contact-Center), Before you begin. Checked 2026-09-30. [^20]: A Google connector is added in Control Hub under Services > Contact Center > Tenant Settings > Integrations > Connectors by choosing the Google card, entering a unique name and uploading the authentication key. Source: [Configure Google connector for Webex Contact Center](https://help.webex.com/en-us/article/ctge8i/Configure-Google-connector-for-Webex-Contact-Center), procedure steps. Checked 2026-09-30. [^21]: The 5 MB maximum and .wav requirement in the Manage audio files article are stated for agent personal greeting uploads, not for audio prompts. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Agent Personal Greetings section, create procedure. Checked 2026-09-30. [^22]: The Manage audio files article states that the system does not support updating audio files that are currently in use. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, note in edit procedure. Checked 2026-09-30. [^23]: The channel's Music on Hold field is described as the music file to use in the Outdial Entry Point. Source: [Set up a channel in Webex Contact Center](https://help.webex.com/en-us/article/ewuay1), channel settings table, Music on Hold. Checked 2026-09-30. [^24]: The Play Message activity cannot be interrupted by DTMF input, but when it sits after Queue Contact it is interrupted when an agent becomes available to take the call. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Message section, note. Checked 2026-09-30. [^25]: If the Play Music duration is shorter than the audio file, the music plays for that duration; if it is longer than the file, the music loops and plays for five times the length of the file. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Music section, Music Duration. Checked 2026-09-30. [^26]: The Play Music start offset moves the starting point inside the file: the documented example is a 60-second file with a 45-second offset and 30-second duration, which plays the last 15 seconds and then loops to play the first 15. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Music section, Start Offset example. Checked 2026-09-30. [^27]: The Play Music activity plays a .wav file while the customer waits in queue and is configured with an audio file, a music duration and a start offset. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Music section. Checked 2026-09-30. [^28]: Flow Designer has a Preview prompt button that plays audio files and text-to-speech messages inside the designer, with a Play all option for both together, so prompts can be checked without publishing the flow or placing a PSTN call. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Preview prompt passages in the prompt settings of IVR activities. Checked 2026-09-30. [^29]: After Queue Contact or Queue To Agent, flow execution continues with the attached activities, and pre-configured music is played to the waiting customer by attaching a Play Music activity. Source: [Understand Routing and Queueing in Webex Contact Center](https://help.webex.com/en-us/article/np2fdx/Understand-Routing-and-Queueing-in-Webex-Contact-Center), Queue Contact activity and Queue To Agent activity sections. Checked 2026-09-30. [^30]: Each queue has a Default music in queue field naming the .wav file played when calls arrive or wait in the queue, and that file is played if Play Music is not configured in the Queue Contact activity. Source: [Create queues and configure routing patterns](https://help.webex.com/en-us/article/ubg5qd), queue settings table, Default music in queue. Checked 2026-09-30. [^31]: A loop after Queue Contact must not contain only a Play Message activity; a loop that combines Play Music and Play Message is a valid call flow. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Message section, note on loops after Queue Contact. Checked 2026-09-30. [^32]: A 2024 Cisco TAC tech note says the global variables Global_Language and Global_VoiceName are not available inside a subflow. Source: [Configure Different Supported Languages and Voice Names with Native Text-To-Speech inside WxCC SubFlow](https://www.cisco.com/c/en/us/support/docs/contact-center/webex-contact-center/222681-configure-different-supported-languages.html), Configure, Step 1 note. Checked 2026-09-30. [^33]: The tech note's workaround is to create two local variables in the subflow named Global_Language and Global_VoiceName, set each with a Set Variable activity, and then use a text-to-speech prompt after them. Source: [Configure Different Supported Languages and Voice Names with Native Text-To-Speech inside WxCC SubFlow](https://www.cisco.com/c/en/us/support/docs/contact-center/webex-contact-center/222681-configure-different-supported-languages.html), Configure, Steps 2 and 3. Checked 2026-09-30. [^34]: The tech note verifies language and voice configuration by placing a call into the flow and listening for the expected language and voice name. Source: [Configure Different Supported Languages and Voice Names with Native Text-To-Speech inside WxCC SubFlow](https://www.cisco.com/c/en/us/support/docs/contact-center/webex-contact-center/222681-configure-different-supported-languages.html), Verify section. Checked 2026-09-30. [^35]: Cisco TTS supports 22 languages with two voices per language, one male and one female, and one of the two is marked as the default for the locale. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Supported languages and voices table. Checked 2026-09-30. [^36]: Webex Contact Center has built-in text-to-speech that converts written text into synthesized audio for IVR. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Overview. Checked 2026-09-30. [^37]: Customers on the Next Generation Voice Media Platform see both a Cisco TTS and a Google TTS connector in the Prompt settings of IVR activities such as Play Message, Menu and Collect Digits. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Overview. Checked 2026-09-30. [^38]: Flow Designer media activities such as Play Message, Collect Digits and Menu support dynamic text-to-speech, where expressions embed custom data in the utterance and SSML adjusts how it is spoken. Source: [Design Delightful Customer Experiences with Webex Contact Center Flow Designer](https://developer.webex.com/blog/design-delightful-customer-experiences-with-webex-contact-center-flow-designer), section on personalising with dynamic text-to-speech. Checked 2026-09-30. [^39]: For en-US the Cisco TTS voice table lists en-US-Daniel (male) and en-US-Maria (female), with the female voice marked as the default. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Supported languages and voices table, en-US row. Checked 2026-09-30. [^40]: To use the default language and voice for Cisco Text-to-Speech, the flow must have the global variables Global_VoiceName and Global_Language configured. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Supported languages and voices, configuration note. Checked 2026-09-30. [^41]: The default Cisco TTS language and voice are overridden in a flow by a Set Variable activity carrying the appropriate voice name code. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), Supported languages and voices, configuration note. Checked 2026-09-30. [^42]: Cisco TTS accepts the SSML tags speak, break, say-as, audio, p, s, prosody and sub. Source: [Text-to-Speech (TTS) in Webex Contact Center](https://help.webex.com/en-us/article/ntkjqhw/Text-to-Speech-(TTS)-in-Webex-Contact-Center), SSML support section. Checked 2026-09-30. [^43]: In Flow Designer a Text-to-Speech toggle on the Menu, Play Message and Collect Digits activities turns on synthesized speech, after which the flow developer selects a TTS connector. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Play Message section, Prompt settings. Checked 2026-09-30. [^44]: The documentation leaves open whether a bulk import can replace an audio file that a flow is using: one article says in-use files cannot be updated, another says a same-named bulk upload replaces the old file, and neither refers to the other (inferred). Source: [Bulk Operations in Webex Contact Center](https://help.webex.com/en-us/article/31e39g/Bulk-Operations-in-Webex-Contact-Center), Audio files section, compared with Manage audio files edit-procedure note. Checked 2026-09-30. [^45]: Audio files must be uploaded in WAV format as mono audio with a sample rate of 8 kHz and 8-bit u-law encoding. Source: [Manage audio files](https://help.webex.com/en-us/article/be12vp/Manage-audio-files), Audio Prompts section, note on audio file format. Checked 2026-09-30. [^46]: The next generation media platform is the default for all new Webex Contact Center trials and subscriptions during activation. Source: [Set up voice channels for Webex Contact Center](https://help.webex.com/en-us/article/2dputx/Set-up-voice-channel-for-Webex-Contact-Center), voice platform statement near the top of the article. Checked 2026-09-30. [^47]: Flow Designer enforces self-loop limits per activity: 100 for Queue Contact, 1,500 for Advanced Queue Information and 750 for Escalate Call Distribution Group. Source: [System limits in Webex Contact Center](https://help.webex.com/en-us/article/n7s6ed7/System-limits-in-Webex-Contact-Center), Flow Designer self-loop limits table. Checked 2026-09-30. [^48]: A text-to-speech message of more than one line requires a Pebble escape filter for the system to play it. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Flow Designer, text-to-speech message guidance. Checked 2026-09-15. [^49]: Cisco instructs that single quotes be used instead of double quotes inside an expression and gives no reason. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), Flow Designer, text-to-speech and expression guidance. Checked 2026-09-15. [^50]: Flow Designer has no version control feature. The flow version number counts how many times the flow has been published, and version labels can be applied. Source: [Build and manage flows with Flow Designer](https://help.webex.com/en-us/article/nhovcy4/Build-and-manage-flows-with-Flow-Designer), flow versioning section. Checked 2026-09-30.