Looks like https://flowroute.com/ may be the way.. Thank to all that responded to my inquiry. Source: over 1 year ago

Add a few bucks to a sip provider and register your ATA to them. I use flowroute.com and voip.ms personally. Source: over 1 year ago

3CX (cost based on (lines/channels), 25 Yealink txx phones, Assuming you have solid internet...port your voice trunks to flowroute.com. Source: over 2 years ago

I'm not 100% certain what you are looking for in terms of "anonymity", but you can purchase/transfer/park numbers at places like voip.ms, numberbarn.com or flowroute.com which can provide you with SMS, voicemail or voice calling. voip.ms is one of the easiest. You can make your outbound Caller ID (referred to as the CNAME record in industry speak) anonymous or to say just about anything within reason. Source: over 2 years ago

Calls are very low bandwidth. With a TINY bit of outbound QoS, your calls should be just fine. I have plenty of clients on Comcast that trunk to other providers like clearlyip.com or flowroute.com. We have hundreds of handsets on FreePBX, and not one uses the ISP for SIP trunks. Source: almost 3 years ago

I’d recommend more modern platforms that are better focussed on good design, ease of use, and suited to small nonprofits: - Kindful - Beacon - Neon. Source: about 1 year ago

Try looking at [Kindful]https://kindful.com) , Beacon, or if you want a free option, CiviCRM. Source: about 3 years ago