The yuusen denwa is a local announcement & video phone. Takamichi’s (my host) parents have one in their living room and it periodically comes alive with local announcements, sent from some central office in Aoki.
For example, at 5pm there is an announcement that…it’s 5pm. I think there was also a stern message for kids to stop playing and go home. The message plays through loudspeakers throughout town and is usually preceded by music, so a few times I’ve been surprised by loud classical music suddenly coming on while we’re working on one of the fields.
Apparently you can also make a 2-way video call with this phone, though I haven’t seen anyone do that.