Last updated · Written for practice managers and office administrators.
The three options
| Question | Analog (POTS) line | VoIP adapter + machine | Online fax, ported number |
|---|---|---|---|
| What you keep | Machine, line, number. | Machine and number; the line becomes an internet phone line. | The number. No machine, no line. |
| Availability | Shrinking. Retired wire center by wire center; AT&T aims to exit most copper by end of 2029. | Anywhere with internet. | Anywhere with internet, on any device. |
| Reliability of the fax call | The baseline fax was designed for. | Depends on the adapter, the provider’s fax support and the connection. Check with your provider. | Our carrier terminates the call on fax servers built for it; the last leg to the recipient’s machine is a normal phone call either way. |
| Power outage | Line-powered; keeps working. | Needs office power and internet. | Inbound faxes land on our servers; read them from a phone. Outbound from any connected device. |
| Monthly cost | Line rental on your bill, plus toner, paper, maintenance. | VoIP seat plus adapter, plus toner, paper, maintenance. | From $19/month (Solo, 300 pages), $15/month billed annually. No overage charges. |
| Records | Paper; the machine’s own log. | Paper; the machine’s own log. | PDF per fax, delivery receipt per fax, audit log of who viewed what; retention you set. |
| Staff workflow | Walk to the machine. | Walk to the machine. | Inbox, email notification, routing by sender; send from a browser or email. |
| Compliance posture | Open tray; no access control. | Open tray; no access control. | Encrypted in transit and at rest, per-user access, audit log. HIPAA BAA coming soon (not yet in force). |
When an analog line is right
If your carrier still sells it in your area and you have a device that must fax on its own — some older diagnostic or laboratory equipment, a stand-alone machine in a location without reliable internet — the analog line is the least-effort answer for as long as it lasts. The catch is the calendar. Discontinuance rules now make it easier for a carrier to retire a legacy voice product (the March 2025 waiver order), and the written notice you get under 47 CFR § 63.71 may arrive with a date that is closer than you would like. Treat an analog line as a bridge, keep the bill handy, and have the port ready to file.
When a VoIP adapter is right
An adapter (an analog telephone adapter, or a VoIP provider’s box with a phone jack) lets the existing machine dial out over an internet phone service. It is the right answer when the machine itself is the requirement: integrated with a multifunction printer that staff rely on, or attached to equipment that only speaks fax.
Be honest about the failure modes. A fax call is two modems negotiating in real time. Compression, jitter or packet loss on the internet path can cause failed or partial transmissions, and long faxes are the most exposed. Whether your provider handles this well is a question for the provider; ask whether fax is supported on the plan you are buying and test with a 30-page document before you cancel the copper line. The number is ported to the VoIP provider in this scenario, so the same porting rules and the same “keep the old line on until it completes” warning apply.
When online fax is right
For most offices — a practice, a firm, an agency — the fax number is what matters and the machine is a cost centre. Porting the number to usfax keeps the number and removes the line, the hardware, the consumables and the walk to the tray. Inbound faxes arrive as PDFs in an inbox with an email notification; outbound faxes go from a browser or from email, with a delivery receipt when the receiving machine confirms every page.
There are cases where it is not the right answer. If a device must send its own faxes unattended, online fax cannot help that device. If your internet connection is unreliable and you cannot use a phone as a fallback, the adapter route is no better, but an analog bridge line might be. And if you handle protected health information today, note that our HIPAA Business Associate Agreement is coming soon: until you have signed it in Settings, the account is not covered by a BAA and must not be used for PHI.
How to decide in ten minutes
- List each fax number and what is plugged into it.
- For each machine, ask: does anything need this machine specifically? If no, online fax.
- If yes: can that device tolerate an adapter, tested with a long fax? If yes, adapter. If no, analog bridge line for as long as the carrier offers it.
- Check the bill for contract terms and bundle pricing before you set a date.
- Run the portability check on every number you intend to keep.