Fix 488 SIP Error for Fax T.38 ReINVITE Rejected by Webex Calling

Publisher

Cisco

URL

https://www.cisco.com/c/en/us/support/docs/unified-communications/webex-calling/222133-fix-488-sip-error-for-fax-t-38-reinvite.html

Published

2024-07-18

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

Cisco website terms of use; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• The 488 tech note presupposes that T.38 mode is already configured in Control Hub on the fax device. in context
• After changing compression to Normal for the 488 T.38 issue, Cisco says the fax device must be restarted for the change to apply. in context
• Cisco's fix for the Webex Calling T.38 ReINVITE 488 error is to set the fax user's or workspace's Call Experience compression to Normal compression in Control Hub on the Calling tab. in context
• A documented Webex Calling fax failure is that the T.38 switchover ReINVITE from a registered fax device is answered with SIP 488 Not Acceptable Here so T.38 is never negotiated. in context

Cite this source record

APA

WarmTransfer. (2024, July 18). Fix 488 SIP Error for Fax T.38 ReINVITE Rejected by Webex Calling. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-technote-222133-wxc-t38-reinvite-488

BibTeX

@misc{warmtransfer-cisco-technote-222133-wxc-t38-reinvite-488,
  title  = {Fix 488 SIP Error for Fax T.38 ReINVITE Rejected by Webex Calling},
  author = {{WarmTransfer}},
  year   = {2024},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-technote-222133-wxc-t38-reinvite-488},
  note   = {Cisco, accessed 2026-09-24}
}