# Recommendation I.251.8 (11/1988): Number identification supplementary services: Sub-addressing (SUB)

> superseded recommendation/international standard from the International Telecommunication Union

**Wikidata**: [Q26985380](https://www.wikidata.org/wiki/Q26985380)  
**Source**: https://4ort.xyz/entity/recommendation-i-251-8-11-1988-number-identification-supplementary-services-sub-addressing-sub-