Landline phone -- generally just works, regardless of Internet status, and still sounds better than cell/VoIP crap. Funny how we accept WORSE sounding phones than we had 10-20 years ago. For VoIP, connection speed isn't the only issue. Latency is a problem as well.

This goes double if you have an old Bell phone that was designed for good sound and durability rather than produced in a 3rd world country to a price point. I'm a tech person, but I also recognize that the best tool for the job can be the "default" one sometimes:

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