00 · Header

T6 · Migration

Third-party PBX & CC to Webex

Cisco names a third-party PBX as a source the Dedicated Instance method has covered, and it names third-party phones as a provisioning case. It does not print an Avaya, Genesys, or Amazon Connect object crosswalk. What it does print is how Webex Contact Center reaches a premises PBX or Microsoft Teams, and how UCCX may sit beside Dedicated Instance.

Expand all sections

01 · Executive summary

Five lines, then why it matters

• Migration Insights reads a Unified CM tar. A third-party PBX export is not that tar. [cite:2] [cite:5]
• The implement article says to work with the third-party vendor for third-party devices and phones. [cite:5]
• Local Gateways such as Cisco CUBE or approved third-party SBCs can be set for +E.164 so they interoperate with an on-premises PBX. Session border controller configuration is the administrator’s work. The voice-channel article does not include vendor-specific SBC steps. [cite:3]
• Microsoft Teams agents use a registration or certificate Local Gateway, CUBE or a third-party SBC, +E.164 on the gateway, and presence sync between Agent Desktop and the Teams client. [cite:3]
• A customer story offers three contact-center approaches beside Dedicated Instance: Webex Contact Center, UCCX on Dedicated Instance IaaS, or UCCX left on premises if the 60 ms round-trip holds. [cite:6]

02 · Architecture map

Where a non-Cisco source actually lands

flowchart LR
  PBX[Premises PBX] --> LGW[Local Gateway]
  TEAMS[Microsoft Teams] --> LGW
  LGW --> WXC[Webex Calling]
  WXC --> WXCC[Webex Contact Center]

03 · Core concepts

What Cisco printed, and what it left blank

Contact center beside Dedicated Instance

Teams and the premises PBX

04 · Ecosystem & sister technologies

Glossary, map, sisters, edges

Glossary

Third-party PBX

A source the Dedicated Instance practice article names. The article does not list vendor objects. [cite:1]

DeviceEligibility.csv

A Migration Insights report that identifies devices eligible to move, including third-party devices. [cite:2]

Dial number

The free-form agent destination in the voice-channel article. +E.164 is typical. Reachability is required. [cite:3]

Direct SIP

The Local Gateway trunk between Webex Calling and a Microsoft Teams tenant for Webex Contact Center agents. [cite:3]

JTAPI

The UCCX call-control interface to Unified CM. The integration article says it is sensitive to latency and must be under 60 ms. [cite:4]

Mind map

mindmap
  root((Third-party source))
    Calling
      Insights CSV
      Control Hub provision
      App Hub
    Contact center
      WxCC agents
      UCCX 60 ms
      Certificate trunks

Sister technologies

Integration edges

Cross-platform bridges

Future hooks

Canon plan. Keep the object-crosswalk row empty until a Cisco page prints vendor fields. Cisco. The practice article already says the method has been used from a third-party PBX. That sentence is historical scope, not a published runbook. [cite:1]

Ecosystem troubleshooting

05 · Flow

From a premises agent to Webex Contact Center

06 · Config

Paths you can cite

1. Read DeviceEligibility.csv from Migration Insights before you schedule a third-party phone. The report names IP phones, Room OS, ATAs, and third-party devices. [cite:2]
2. For a device with no enterprise-to-cloud firmware path, add it in Control Hub. The guide’s replacement example is ATA 191/192. Work with the vendor when the implement article says to. [cite:2] [cite:5]
3. On the Local Gateway, build a dial plan that matches the premises agent destination in E.164 and +E.164 if agents will sign in either way. [cite:3]
4. For Microsoft Teams agents, use a registration or certificate Local Gateway and the CUBE direct-routing PDF, or the SBC vendor’s guide. Include trunks, route groups, and unknown-extension routing. [cite:3]
5. For Dedicated Instance agents on Webex Contact Center, use the certificate inter-op trunk. Do not revive a registration trunk for that path. [cite:4]
6. If UCCX stays on premises and Unified CM moves into Dedicated Instance, measure round-trip time and stop if it is not under 60 ms. [cite:4]

07 · Limits

What is quantified

08 · Troubleshooting

Ten misses

09 · Self-question ladder

Twelve rungs

10 · Lab

A paper lab. Do not attach a production SBC to learn this.

• Goal: classify six designs as supported, unsupported, or TODO-verify using only the cited pages.
• Prereq: articles 2dputx, nmhk7ve, tf6kpq, and the December 2025 deployment guide section on third-party devices. No customer org you do not administer.
• Step 1. A spreadsheet of Avaya stations is renamed to a tar. Expected: Insights still expects a Unified CM export.
• Step 2. PSTN delivers straight to a Teams client. Expected: not supported.
• Step 3. UCCX in a US branch, Unified CM in Dedicated Instance, RTT 90 ms. Expected: outside the printed constraint.
• Step 4. Write the dial-number rule. Expected: free-form, typically +E.164, reachable.
• Evidence: the certificate-trunk sentence and the App Hub URL.
• Break it: teach round robin as a Webex Contact Center queue pattern because the Calling test list says it. Recovery: put that sentence back on T6-R08.
• Reflection: which vendor crosswalk you still cannot cite.

11 · Quiz

Twelve questions

12 · Audio

Slots for Studio

13 · Interview

Oral answers

30 seconds. Cisco says the Dedicated Instance method has been used from a third-party PBX. The migration tools still eat a Unified CM tar. Third-party phones are provisioned in Control Hub when they have no firmware conversion. There is no Avaya field map in the pages this room cites.

2 minutes. Webex Contact Center can send an agent call to a premises PBX, a DID, or a cell, through Cloud Connected PSTN or a Local Gateway. The gateway is CUBE or an approved SBC, and the administrator owns the SBC lines. A dial number is free-form. Plus E.164 is the usual form and is not mandatory, but the number has to be reachable. Microsoft Teams agents use Direct SIP on that same gateway class, with presence sync. Cisco does not support handing Webex Calling PSTN calls straight to Teams endpoints.

30 seconds, UCCX. If UCCX stays on premises and Unified CM moves into Dedicated Instance, JTAPI round-trip must be under 60 milliseconds. The integration article says most AMER premises links will miss that. The customer story’s other choices are Webex Contact Center, or UCCX bought separately and placed on Dedicated Instance IaaS.

2 minutes, trunks. Dedicated Instance into Webex Contact Center uses certificate trunks. Registration trunks are no longer the supported inter-op. Inbound can arrive on a Local Gateway into multi-tenant and then the contact center, or on Cloud Connected PSTN. Do not reuse the Calling acceptance phrase “round robin, longest idle, or simultaneous ring” as if it were the Webex Contact Center queue catalog.

What you will not say. You will not invent an Avaya, Genesys, or Amazon Connect crosswalk. You will not paste IOS from the CUBE PDF into an answer you have not opened. You will not call App Hub a migration tool.

14 · Citations

1. Best practices in preparation and migration process to Webex Calling - Dedicated Instance — help.webex — article tf6kpq — help.webex.com article tf6kpq — retrieved 2026-10-14. The retrieved markdown did not print a header date. re-check Source platforms include third-party PBX. No object crosswalk in that sentence.
2. Calling: Transitioning from Unified CM to Webex Calling — Cisco deployment guide — December 2025 — cisco.com DEPLOYMENT_CALLING_Unified_CM_to_Webex_Calling.pdf — retrieved 2026-10-14. DeviceEligibility.csv includes third-party devices. No firmware path for many non-phone devices. ATA 191/192 example. App Hub calling catalog. No native migration of Unity Connection messages or greetings.
3. Set up voice channels for Webex Contact Center — help.webex — article 2dputx — help.webex.com article 2dputx — retrieved 2026-10-14. The retrieved markdown did not print a header date. re-check Premise PBX and Microsoft Teams agents. Direct SIP. No direct PSTN-to-Teams connection. Dial number rules. CUBE PDF pointer. SBC configuration is the administrator’s.
4. Webex Dedicated Instance Contact Center integration — help.webex — article nmhk7ve — help.webex.com article nmhk7ve — header June 27, 2025, retrieved 2026-10-14. re-check UCCX placements. JTAPI under 60 ms. Certificate trunks for Dedicated Instance to Webex Contact Center. Registration trunks no longer supported on that inter-op.
5. Implement the migration from Unified CM to Webex Calling — help.webex — article q0pgpb — help.webex.com article q0pgpb — retrieved 2026-10-14. Third-party devices and phones: work with the vendor. User and feature tools consume Unified CM exports. Queue acceptance language is a Calling test, kept out of the Webex Contact Center pattern list.
6. Dedicated Instance – customer deployment models — help.webex — article ny65x1bb — help.webex.com article ny65x1bb — retrieved 2026-10-14. The retrieved markdown did not print a header date. re-check Contact-center story: Webex Contact Center, UCCX on IaaS, or on-premises UCCX if 60 ms holds.
7. Design to migrate from Unified CM to Webex Calling — help.webex — article nqojzwt — help.webex.com article nqojzwt — retrieved 2026-10-14. Basic emergency calling wants at least one customer-owned +E.164 per Webex Calling location. Used here only as the boundary for a PBX callback number.

15 · Re-engineer later

• Open questions: header dates for tf6kpq, 2dputx, ny65x1bb, and nqojzwt. A Cisco page that prints Avaya, Genesys, or Amazon Connect objects.
• Facts still marked TODO-verify: vendor object crosswalks; a Control Hub ingest for a non-Cisco PBX export; a vendor recording bridge.
• Facts still marked re-check: the 60 ms sentence and the voice-channel numeric-free rules whose headers are old or missing.
• Assets missing: voice-channel diagram export, audio.
• Ideas for v1.0: a one-row card that says “named source” versus “printed procedure” for every PBX this track meets.
• Next review: re-check nmhk7ve before teaching the 60 ms figure in a design review.