Have a super small office that uses a step up from a home 2.4Ghz phone setup. They have been using Spectrum’s phone system that provides 2 analog phone lines straight from the ISP modem.

The office is switching to AT&T fiber but they can not offer their similar phone system to the area in any reasonable amount of time.

So I am looking for a basic VoIP provider that offers an analog handoff for the 2 lines they need. I see Vonage offers a box that does this https://support.vonage.com/articles/answer/Vonage-Box-VDV22VDV23-Telephone-Adapter-1041 but not sure if that is for business or residential service, not that it really matters to the office.

Is there some other provider that I should be looking at? This is very basic, nothing past having the line ring is needed.