Introduction of the monophone - first hand set telephone of modern type 收发话机问世，这是一种款式新颖的手持电话。
2.
Development of unattended private automatic branch exchanges . two - line monophones introduced 开发无人自动小交换机。二线制收发话机问世。
3.
Commercial ship - to - shore telephone service opened . u . s . navy begins use of strowger equipment . monophones made available in color 商业轮船与陆地之间的电话业务开通。美国海军开始使用史端乔设备。彩色收发话机诞生。
