Technical requirements for private branch exchange (PBX) systems
By: Nippon Telegraph & Telephone Public Corporation.
Contributors: Nihon Denshin Denwa Kōsha.
Series: NTT technical requirements
Publisher: The Telecommunications Association
Published: 1980
Place of publication: Tokyo, Japan
Language: eng
Number of pages: 18
Subjects: Telephone -- Private branch exchanges.
Notes: Cover title.