# Recommendation F.220 (11/1988): Service requirements unique to the processable mode number one (PM1) used within the teletex service

> superseded recommendation/international standard from the International Telecommunication Union

**Wikidata**: [Q26985349](https://www.wikidata.org/wiki/Q26985349)  
**Source**: https://4ort.xyz/entity/recommendation-f-220-11-1988-service-requirements-unique-to-the-processable-mode-number-one-pm1-used-within-the-teletex-service