Line card for key telephone systems adapted to provide music during hold condition
作者： Richard A Marshall
DOI:
关键词: Telephone line 、 Class 5 telephone switch 、 Engineering 、 Telecommunications 、 Telephone switchboard 、 Class 4 telephone switch 、 DMS-100 、 Telephone exchange 、 Line card 、 Mobile radio telephone 、 Electrical engineering
摘要: A key telephone system line card that includes provisions for supplying music to a connected subscriber when instrument associated with the is operated in hold condition. The two winding relay included conventional utilized provide transformer coupling from source line.
lens.org 参考文章(2)
Levy Alfred, Telephone hold program system ,(1962)
G Merritt, G Kaner, R Kemmerly, Telephone audio program system ,(1973)