Webex Contact Center voice channel and PSTN options

Verified 2026-09-05 · 46 claims · sources tier 2

Also known as Common Edge, RTMS, vPOP.

Webex Contact Center administrators can choose from three Webex Cloud PSTN interconnectivity options: Webex Contact Center PSTN, Webex Cloud Connected PSTN, and Cisco Calling Plan, plus an on-premises option, Webex Calling Local Gateway 22. Webex Contact Center and Webex Calling share a global network of Common Edge access services, which lets calls route into Webex Contact Center using Webex Calling PSTN services without requiring a Webex Calling subscription 12.

PSTN Interconnectivity and Calling Options

Webex Contact Center PSTN is the Cisco-billed PSTN bundle and is available only in the contiguous United States and Canada 15. This option does not support international dialing and only delivers calls to or from North American Numbering Plan destinations in the lower 48 states or Canada 14.

Webex Cloud Connected PSTN, also called Cloud Connect or CCCP, provides PSTN connectivity in over 65 countries through Certified Calling Providers 10. Using this option requires the customer to partner directly with a Cloud Connected PSTN provider who handles service initiation and activation, billing, and phone number allocation 11. Cisco also distinguishes integrated from non-integrated Cloud Connected PSTN providers, where an integrated provider supplies ordered numbers directly into Control Hub for automatic display, while numbers from non-integrated providers do not arrive that way 7. Furthermore, Cisco names authorised Cloud Connected PSTN providers as Cloud-Connected PSTN Partners (CCPP), routing inbound and outbound calls for a location over the connection established with the selected partner 8.

Webex Calling Local Gateway allows a customer to keep its existing on-premises PSTN carrier while providing access in over 140 markets globally 24. The Local Gateway is the customer's own Session Border Controller (SBC) that registers with Webex Calling and routes calls between Webex Calling and on-premises resources such as agents or existing PSTN connectivity 26. Local Gateway deployments requiring more than 250 concurrent calls for IVR and agent calls combined must use a Certificate Based trunk type to encrypt SIP and RTP toward the Webex Global Media network, whereas a Registration Based trunk is used for up to 250 concurrent calls 25.

The Cisco Webex Calling Plan as a Contact Center PSTN option is currently available only for Webex Contact Center trials, and otherwise only in regions where Cisco supports service and or inbound toll-free numbers 9. All new Webex Contact Center subscriptions automatically include the Webex Calling PSTN services needed for Common Edge, whereas tenants provisioned before October 2024 may need their partner to add Webex Calling PSTN service to use Common Edge services 30. Additionally, the Cisco Webex Contact Center Setup and Administration Guide describes a Voice Services Platform (VSP) as an alternative PSTN service option alongside Webex Calling, with Voice POP as its default telephony option, though this applies only to customers with a Voice Services Platform subscription 38.

Agent Connection Methods and Desktop Preferences

Agents can connect to Webex Contact Center via five methods: Webex PSTN inter-connectivity using PSTN DID or cellular agents, Webex Calling registered endpoints like MPP devices or the Webex App requiring a valid Webex Calling subscription, WebRTC Agent Desktops, premise-based PBX or PSTN agents, or Microsoft Teams agents via Local Gateway Direct SIP Routing 21. When logging in, agents choose a preferred call destination from three types: Dial Number which is a free-form DID-style number typically in +E.164 format but not mandatory, Extension which is a short internal number matched to a Webex Calling or UC endpoint, or Desktop for WebRTC calling in the browser 6.

WebRTC agent calling requires a minimum network bandwidth of 100kbps per call 43. WebRTC is enabled by default for new tenants to let agents and supervisors make or receive calls directly in the browser via the Desktop option 42. However, WebRTC Desktop support is currently unavailable for customers hosted in the Japan data center 44. Cisco does not recommend enabling voicemail on an agent line because an incorrectly configured setup could route a customer call to voicemail while the contact center incorrectly believes the call was answered normally 39.

Routing, Media, and Signaling Requirements

An Entry Point is the configuration object associating an inbound telephone number with an IVR service flow, and inbound numbers must be mapped to entry points during PSTN provisioning 20. When an entry point is configured with both an E.164 number and an extension, Webex Contact Center always reports the call against the E.164 number even if the extension was dialed 19. Administrators can assign a PSTN Region to an entry point telephone number in Control Hub to determine where in Webex's global edge network the contact center processes voice media to minimize latency for geographically distributed deployments 31.

Calls arriving at Webex Contact Center must use codec G.711uLaw or G.711aLaw with DTMF via RFC2833 23. Any other codec such as G.729, iLBC, or Opus must be transcoded externally before reaching Webex Contact Center, because Webex Contact Center provides no transcoding or media termination point service 23. Regarding SIP interoperability, SIP Early Offer is not supported and listed as a future roadmap item, SIP Delayed Offer is supported, SIP Early Media is not supported and also listed as a future roadmap item, and the SDP packetization timer must be set to 20ms 33. For call quality, Webex Contact Center supports at most a single upstream or northbound PSTN carrier forwarding calls into the connected PSTN service, and forwarding through a second intermediary carrier before reaching Webex Contact Center is explicitly unsupported due to added latency 29.

A customer cannot map a toll-free number to an entry point without the appropriate entitlement, which on Cisco PSTN telephony type requires the Cisco Bundle 2 Inbound toll-free number access add-on 36. The number of concurrent voice contact sessions a tenant is entitled to is computed by the formula ((committed Standard Agent licenses + committed Premium Agent licenses) * 3) + number of Add-on IVR port licenses, and this entitlement value cannot be modified directly by the customer 13. For zero-commitment orders, the default Concurrent Voice Contact Entitlement is 100 plus the number of Add-on IVR port licenses 45. The default surge percentage allowing concurrent voice contacts to exceed the base entitlement is 30% 34. If the calculated Maximum Concurrent Voice Contact Threshold is insufficient, the customer must submit a service request to Cisco Support rather than modifying it in Control Hub 35.

Dedicated Instance Integration

Webex Contact Center integrates with Dedicated Instance via two deployment options: Option 1 where the agent phone is on the Webex Calling multitenant platform and call routing crosses to Dedicated Instance for back-office users via a default inter-op SIP trunk, and Option 2 where the agent phone is on Dedicated Instance using either a Dedicated Instance Local Gateway or multitenant Cloud Connected PSTN for PSTN connectivity 18. Cisco requires certificate-based mTLS SIP trunks for Webex Dedicated Instance to Webex Calling multitenant Contact Center integration, as registration-based trunks are no longer supported 17. For Dedicated Instance agents to work with Webex Contact Center, administrators must create or modify an Audio Codec Preference List on the default inter-op SIP trunk region, ordering codecs as G.711 U-Law first, then G.711 A-Law, then OPUS 16.

Regional Architecture and Media Edge

The Webex Contact Center Architecture article publishes a media edge region table listing US cities including Chicago, Dallas, Los Angeles, and New Jersey, Canada cities Vancouver and Toronto, Brazil city Sao Paulo, Europe cities Frankfurt and Amsterdam, United Kingdom cities Manchester and London, India city Mumbai, Singapore, Japan cities Tokyo and Osaka, Australia cities Melbourne and Sydney, and Middle East and Africa cities South Africa Cape Town and the UAE 27. As of a September 3, 2026 change-log entry, Cisco removed Saudi Arabia from the Next Generation Media Services AWS Region column of the architecture regions table, though Saudi Arabia remains listed for general Webex CC Services in that region 32. For multinational deployments, Webex Contact Center is architected to keep voice media local to the region where the customer and agent voice media edge or ingress services run, rather than backhauling all media to a single region 28.

Applicability

• Vendors: Cisco
• Products: Webex Contact Center, Webex Calling, Webex Dedicated Instance, Webex Control Hub
• Deployment: Cloud, On-Premises, Dedicated Instance
• Releases covered: Current as of 2026-09-04

What remains uncertain

• Field reports suggest and this is inferred: WarmTransfer infers that Cisco has withdrawn vPOP as a documented Webex Contact Center PSTN option because the onboarding guide has expired and the voice-channel article's change log records removing its vPOP reference, though no official end-of-sale or end-of-service notice confirms this 40. Readers should verify current support status directly through active Cisco documentation and release notes.

WarmTransfer. (2026, September 5). Webex Contact Center voice channel and PSTN options. WarmTransfer. https://warmtransfer.net/knowledge/webex-cc-voice-channels

@misc{warmtransfer-webex-cc-voice-channels,
  title  = {Webex Contact Center voice channel and PSTN options},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/webex-cc-voice-channels},
  note   = {Verified 2026-09-05}
}