Kanji in the window of a three-story building near JR Okachimachi Station in central Tokyo advertise "denwa tokubai" (discounted telephone lines).

But telephone line broker Miyama Denwa's sign goes largely unnoticed by the hordes of passersby, who if anything are more likely to notice the famous mermaid logo of a Starbucks coffee shop next door.

Morinobu Hasegawa, the 46-year-old second-generation owner of the firm, knows that just like the sign, his family business -- and that of nearly 300 private-sector traders in land lines -- is on the wane.