Source note · Call blocking and analytics labeling remediation
Under amended 64.1200(k)(9), the appropriate response code is SIP 603+ as defined in ATIS-1000099 for calls terminating on an IP network, and ISUP cause code 21 with cause location 'user' for calls terminating on a non-IP network.
Checked 2026-09-24
- Vendor
- FCC
- Product
- 47 CFR 64.1200
- Subsystem
- blocking-notification
- Deployment
- pstn
- Region
- us
- Release range
- as amended by FCC 25-15
- Checked
- 2026-09-24
Sources
- Advanced Methods To Target and Eliminate Unlawful Robocalls (final rule; FCC 25-15), 90 FR 13416 — Office of the Federal Register / Federal Communications Commission · tier 1 standards and regulators · Final rule text, amended § 64.1200(k)(9)(i)-(ii)
Cite this note
APA
WarmTransfer. (2026, September 24). Call blocking and analytics labeling remediation: source note call-blocking-labeling-603plus-ip-isup21-tdm. WarmTransfer. https://warmtransfer.net/knowledge/claims/call-blocking-labeling-603plus-ip-isup21-tdm
BibTeX
@misc{warmtransfer-claim-call-blocking-labeling-603plus-ip-isup21-tdm,
title = {Call blocking and analytics labeling remediation: source note call-blocking-labeling-603plus-ip-isup21-tdm},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/call-blocking-labeling-603plus-ip-isup21-tdm},
note = {Source note call-blocking-labeling-603plus-ip-isup21-tdm, checked 2026-09-24}
}