NTT permission to procure a phone line
Historical term for the right to have a telephone line installed by NTT, often required in the past. Now largely obsolete with modern telecom services.
In the past, you needed a subscription right to get a phone line installed.
The price of the subscription right varied by region.
Compound of 加入 (かにゅう, 'subscription, enrollment') and 権 (けん, 'right'). The term specifically refers to the right to subscribe to NTT's telephone service.