Cheat code
Config checklist
- Line CSS before device CSS.
- Emergency partition before any 9.@ partition.
- Inbound dial-peer named. Dial-peer 0 means you missed.
- Early offer or delayed offer written down per leg.
- Webex location PSTN model named before the trace.
- Teams connectivity type named before the SBC trace.
Sources: CUCM 15 system configuration, Webex Calling help, Direct Routing plan.
Sources and go deeper
Opened 2026-10. A row marked confirm has no link, because that page was not verified.
- Cisco. System Configuration Guide for CUCM, Release 15 last checked 2026-10
- Cisco. Cisco Unified Communications Manager product support last checked 2026-10
- Webex. Get started with Webex Calling last checked 2026-10
- Community. Cisco Community, Collaboration knowledge base last checked 2026-10
- Wikipedia. Voice over IP (Wikipedia) last checked 2026-10
- Cisco. Collaboration 12 SRND book. confirm. The historical Collaboration 12 SRND path opened as a product listing, not the design book. Use the Preferred Architecture index, which was opened. last checked 2026-10