# Recommendation I.255.1 (11/1988): Community of interest supplementary services: Closed User Group (CUG)

> superseded recommendation/international standard from the International Telecommunication Union

**Wikidata**: [Q26985413](https://www.wikidata.org/wiki/Q26985413)  
**Source**: https://4ort.xyz/entity/recommendation-i-255-1-11-1988-community-of-interest-supplementary-services-closed-user-group-cug-