Japanese habit/custom ~1~ A bow while they talk on the phone

  I would like to introduce a funny habit of Japanese people.
If you come to Japan, you may have the chance to see Japanese people
make a bow while they are talking on the phone.
 Japanese people make a bow when they meet someone.
We do that for greeting. We do that when we appreciate to someone.
And we also do that when we apologize to someone.
 Maybe there are a lot of meaning when we make a bow.

   Japanese people sometimes make a bow while we talk on the phone.
Maybe you see this in the house. And older people sometimes do this.
Japanese business man or woman may be trained to do so.
(But in my case, I have never been asked to do so in my company)
 But why do we make a bow when we talk on the phone?
While we talk by phone, we can't see the other talker. So, it seems nonsense.

 Japanese people may think it shows the politeness to the other person.
That behavior is not visible for the other person. But he or she may believe
the other talker would understand his or her politeness.
Japanese people may believe the talker's mind would affect to the voice unconsiously.
So we treat politely even if the other talker don't see you.

 That is my understanding.

  If you talk about this habit to Japanese people, they may feel it is funny.
Because Japanese people also think it is strange.
When I saw it in my childhood, I used to see it so strange.

Thank you for reading!