Seeking External Ringer With Crescendo

Hello, Telecom Gurus.

My aging father spills his drink every time the phone rings. He's
going deaf and blind, but refuses to turn the ringer down from "747"
to "air horn".

I've seen in alarm clocks and cell phones, where ringing volume starts
softly, and rises over time. But I've yet to find an external ringer
for a landline that does the same. Any suggestions are appreciated,
as they would save weekly trips to the dry cleaners.

(Visual ringers (strobes) and vibrators induce the same panic
response.)


Cheers,

Jeff

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