# Headsets, and the call that only fails one way · Learn it in 5 minutes

- USB noise-canceling headsets are the recommendation. Analog headsets are not supported. Wireless is not recommended once you are above roughly ten agents. Windows 11 Efficiency Mode can drop live calls. Java admin is not the Mac ARM path; use the web admin there. None of that is a SIP trunk, and all of it still stops a call.
- When audio fails, walk the stack this track just built: path type, codec, bandwidth medium, NAT, TLS, then the headset. The topology tool lets you pull the ITSP or the SBC and hear the symptom described. It is a model.

## Sources and go deeper

- [Technical requirements PDF](https://documentation-be.five9.com/bundle/five9-technical-requirements/raw/resource/enus/five9-technical-requirements.pdf). vendor. last checked 2026-10. Fetched for this lab in October 2026. Re-read before you buy hardware or open a firewall.
- [RFC 3261, SIP: Session Initiation Protocol](https://www.rfc-editor.org/rfc/rfc3261). rfc. last checked 2026-10.
- [RFC 3550, RTP](https://www.rfc-editor.org/rfc/rfc3550). rfc. last checked 2026-10.
- [RFC 3551, RTP profile for audio and video](https://www.rfc-editor.org/rfc/rfc3551). rfc. last checked 2026-10.
- [ITU-T G.711](https://www.itu.int/rec/T-REC-G.711). standard. last checked 2026-10.
- [RFC 8446, TLS 1.3](https://www.rfc-editor.org/rfc/rfc8446). rfc. last checked 2026-10.
- [RFC 1918, private internet addresses](https://www.rfc-editor.org/rfc/rfc1918). rfc. last checked 2026-10.
- [RFC 4787, NAT behavior for UDP](https://www.rfc-editor.org/rfc/rfc4787). rfc. last checked 2026-10.