POTS replacement is the work of moving devices and services off copper analog phone lines, known as plain old telephone service (POTS), onto a newer connection that still presents them with a working phone line. Most solutions use a small on-site device that gives fire alarm panels, elevator phones, gate and door entry systems, fax machines, point-of-sale terminals and modems a normal phone jack, then carries their traffic over cellular, broadband or both. The goal is to keep life-safety and operational devices working as copper lines become scarcer and more expensive.
At a glance
- Copper phone lines are being retired or repriced by many carriers, but plenty of building systems still depend on them.
- Replacement devices emulate an analog line and connect over cellular (LTE or 5G), broadband or both, with battery backup.
- Life-safety lines (fire alarms, elevator phones) need approval from the local authority having jurisdiction and your monitoring company.
- Fax, alarm and modem signals are sensitive; use services built and tested for them rather than assuming ordinary VoIP will work.
- A full inventory of existing lines, including forgotten ones, is usually the first and hardest step.
What problem it solves
For decades, businesses relied on copper analog lines for devices that need a simple, always-on phone connection. Fire alarm panels call the monitoring center, elevator phones reach help, gates and door entry systems call a front desk, and fax machines and card terminals dial out. Many organizations have dozens or hundreds of these lines spread across sites, often billed on old accounts nobody reviews.
Carriers in many areas are retiring copper networks or no longer offering new analog lines, and the price of the remaining lines has risen. In the US, regulators have in recent years made it easier for carriers to discontinue legacy services, though notice requirements and timing vary by carrier, state and service. When a copper line fails or is withdrawn, the device behind it can stop working without anyone noticing until it is needed.
A properly selected, approved, installed and tested POTS replacement service can keep those devices working on a supported connection. Depending on the provider and the copper rates you pay today, it may also cost less per line, and many services add remote monitoring so you know when a line is down.
How it works
A typical solution has three parts:
- An on-site device that provides one or more analog phone ports. Some are purpose-built POTS replacement units; simpler cases use an analog telephone adapter (ATA).
- One or more network connections. Many services use LTE or 5G cellular as the primary path because it is independent of the building’s network, with broadband as a second path, or the reverse. Dual-carrier cellular is available from some providers.
- A service platform that connects calls to the public telephone network, handles 911 calls where applicable, and monitors each line’s signal, power and connectivity.
Most devices include a battery so they can keep working for a period during a power outage. How many hours it lasts, and whether that is enough, depends on the device and on the codes that apply to the equipment it serves.
Signal handling. Fire alarm panels and fax machines send tones that ordinary voice compression can distort. POTS replacement services typically use codecs, settings and testing designed to carry these signals reliably, and some alarm panels can switch to a direct cellular or IP communicator instead of a phone line. Fax can also move to fax over IP (FoIP) using a protocol such as T.38.
Approvals. Fire alarm communication is governed by fire codes (NFPA 72 is widely adopted in the US) and the local authority having jurisdiction, and elevator emergency phones by elevator codes and local inspectors. What is acceptable varies by location, so involve the alarm vendor, the monitoring company and the inspector before cutover.
When it matters for buyers
- When a carrier sends a discontinuation or price increase notice for analog lines.
- When copper lines fail and repairs take too long, especially on life-safety devices.
- When auditing telecom spend, since old analog lines are a common source of waste and forgotten charges.
- When a building inspection or alarm upgrade is coming, which is a natural time to change the communication path.
- When acquiring sites or consolidating carriers, because analog lines are often undocumented.
Questions to ask vendors
- Is your solution listed or approved for fire alarm and elevator use in our locations, and will you help with inspector sign-off?
- Which cellular carriers and network paths does the device use, and does it fail over automatically?
- How many hours of battery backup does it provide, and can that be extended?
- Which devices have you tested: our specific alarm panels, elevator phones, fax machines and card terminals?
- How does the service handle 911 calls and send the correct address?
- What monitoring and alerts do we get when a line, signal or battery has a problem?
- What is the per-line price, what equipment cost is involved, and what are the term and early termination terms?
- Who handles installation, testing and number porting at each site?
How it differs from the PSTN
The public switched telephone network (PSTN) is the overall network that connects phone numbers worldwide. POTS is one way of connecting to it: an analog copper line from the local phone company. POTS replacement changes how a device reaches the phone network. When the replacement service is compatible with the device, approved where required, configured and tested, it can keep calls reaching the destinations the device needs, such as an alarm monitoring center or an elevator emergency line.
For buying guidance, see our POTS replacement solution page.
Problems this helps with
- Our phone company is raising copper line prices or discontinuing them
- Fire alarms, elevator phones and gates still depend on old phone lines
- Dozens of analog lines across sites that nobody has inventoried
- Fax and alarm calls failing on a VoIP line
