The Three Communication Paths
Your alarm panel needs a path to the monitoring center. For decades, that path was a phone line. Today there are three options — and the one you choose has real consequences for system reliability during exactly the moments when reliability matters most.
| Path | Uptime | Cut Risk | Monthly Add-On | Recommended |
|---|---|---|---|---|
| Cellular LTE | Carrier-grade | Cannot be cut from outside | $5–$15 | Yes — primary |
| IP / Broadband | High, ISP-dependent | Router can be cut or jammed | $0–$5 | Secondary path only |
| POTS Landline | Declining | Phone line can be cut at NID | $0 (bundled) | No — legacy only |
Cellular LTE: The Current Standard
Modern alarm panels include a cellular communicator that uses a dedicated SIM card — separate from your home internet and your personal phone — to send encrypted signals over 4G LTE or 5G networks. This path has three important properties:
- Cannot be cut at the premises: There is no wire to cut. An intruder who cuts your phone line or pulls your internet router does not affect cellular communication.
- Independent of home infrastructure: Internet outages, ISP maintenance, and router failures don't affect cellular alarm transmission.
- Fast: Cellular signals typically reach the central station in under 5 seconds. This is faster than IP in most real-world conditions because cellular communicators have optimized, always-on connections to the monitoring network.
The only failure mode for cellular is carrier network outage — which is rare, brief, and affects all subscribers in an area simultaneously rather than targeting individual properties.
Cellular communicators in the St. Louis area typically run on Verizon or AT&T LTE networks. Ask your installer which carrier the communicator uses and verify coverage at your address before installation.
IP / Broadband: Useful as a Backup
Alarm communicators can also send signals over your home or business internet connection. This is faster and cheaper than cellular when it works — but it has two structural vulnerabilities in a burglary scenario.
First, your internet router is typically near your electrical panel or in an exposed closet. An intruder who knows to unplug the router eliminates your IP communication path in under 10 seconds. Second, many homes have managed internet outages — maintenance windows, ISP issues, power-cycling routers — that have nothing to do with security threats but still break monitoring.
IP is best used as a secondary path alongside cellular — not as the primary. Dual-path systems that send over both simultaneously offer the best redundancy.
POTS Landline: A Legacy Technology
Plain Old Telephone Service was the original alarm communication path. The alarm panel dials the central station over a copper phone line, just like a fax machine. It remains in use primarily in older installations that were never upgraded.
POTS has three significant problems in 2025:
- Physical vulnerability: The Network Interface Device (NID) — where your phone line enters the building — is accessible from outside and unprotected. Cutting the line is trivial and takes seconds with a pair of wire cutters.
- Carrier sunset: AT&T and other carriers have been actively petitioning to discontinue POTS service. Some areas have already lost reliable landline infrastructure. This trend will accelerate.
- Slow signal transmission: Phone-line dialers are slower than cellular or IP — typically 30–60 seconds to complete a handshake with the central station versus under 5 seconds for cellular.
Cutting a phone line before entering is a known burglar tactic. If your alarm system still communicates over a landline only, upgrading to cellular communication should be a priority — it's typically a $200–$350 communicator swap, not a full system replacement.
Dual-Path Systems: The Recommended Configuration
The most resilient configuration is cellular primary + IP secondary. Both signals are sent simultaneously on every alarm event. If cellular fails (rare), IP takes over. If IP fails (more common), cellular covers it. If both fail simultaneously — which requires both a carrier outage and a local internet issue — that's genuinely unusual.
All Philibert Security installations use cellular communication as the primary path. Dual-path is available on all plans and recommended for businesses, multi-family properties, and any customer with an elevated risk profile.
The Cellular Communicator Lifespan Issue
One practical concern: cellular communicators are tied to specific network generations. The 3G shutdown in 2022 rendered thousands of legacy communicators non-functional nationwide. Most 4G LTE communicators should remain viable through the 2030s, but check the communicator in any existing system you're evaluating. If it says 3G or CDMA, replace it immediately.