| English | eng-000 |
| primary system | |
| 普通话 | cmn-000 | 一次回路 |
| 普通话 | cmn-000 | 一次系统 |
| 普通话 | cmn-000 | 主系统 |
| 普通话 | cmn-000 | 值统 |
| English | eng-000 | host system |
| English | eng-000 | main system |
| English | eng-000 | major system |
| English | eng-000 | primary circuit |
| English | eng-000 | primary loop |
| íslenska | isl-000 | aðalkerfi |
| русский | rus-000 | основная система |
| русский | rus-000 | первичная система |