How we helped British Telecom detect copper cable theft before the damage was done
This project typifies our approach: practical engineering focused on the fastest path to a reliable outcome. By combining low-power design, robust sensing and ubiquitous comms inside hardware BT already trusts, we delivered a solution that protects critical infrastructure without drawing attention to itself. It’s engineering that respects the operational reality: simple to install, hard to spot, and ready to work for years.
If you manage distributed, unpowered assets and need early-event detection – covers, doors, hatches, gates or environmental triggers – we can help tailor a covert, low-maintenance solution using proven sensing and GSM/IoT comms. Get in touch to explore options for your estate.
BT needed a reliable way to detect copper cable theft the instant it started. Conventional patrols and reactive measures were too slow; by the time a break was discovered, damage, service disruption and safety risks were already a reality. TAD was asked to design a covert, battery-powered device that would live inside BT’s existing infrastructure, sense the tell-tale act of a cover being lifted, and send immediate alerts to nominated responders – without advertising its presence.
We designed the TAD-220, a compact GSM signalling device that installs inside the same IP-rated enclosure BT already uses for splicing and terminations. From street level, nothing new is visible – no extra boxes, no fresh mounts – preserving covert operation and simplifying roll-outs across a wide estate.
A light-dependent resistor (LDR) in the lid detects cover movement by sensing sudden light ingress. That direct physical cue minimises false triggers from vibration or temperature changes and ensures the system reacts to the event that matters most: the moment the cover is disturbed.
On trigger, the unit sends SMS alerts via GSM to pre-programmed numbers – fast, ubiquitous and robust. SMS ensures responders receive notifications even where data coverage is patchy, and multiple recipients can be configured for redundancy and clear escalation.
A custom PCB and ultra-low-power firmware are paired with a SAFT LSH20 3.6V D-cell lithium battery, balancing capacity with field serviceability. The device spends most of its life in deep sleep, waking instantly on trigger to send alerts, then returning to low-power standby – all to maximise years-long deployment with minimal maintenance.
Because the TAD-220 fits inside a standard enclosure, installation is quick and consistent. There’s no need for new chambers, civil works or visible fittings, cutting cost and reducing the risk of discovery and tampering.
The solution had to be practically invisible, simple to install at scale and exceptionally frugal with power. It needed to work in dark, damp chambers and withstand years of inactivity punctuated by split-second events. False positives would waste call-outs; missed events would be costly. Connectivity also mattered: the device had to reach BT’s responders from below ground and remote roadside locations, without any dependency on site power or local networking. And critically, everything had to fit neatly into BT’s existing IP-rated hardware to avoid new approvals or installation complexity.
With the TAD-220 in place, BT gained early warning of theft attempts, allowing faster response before extensive damage occurs. The approach has helped reduce losses, shorten outages and improve safety for both the public and field engineers by flagging activity at the moment it starts – often before cables are fully compromised. The solution’s covert nature, long battery life and straightforward install make it feasible to deploy at scale across vulnerable locations, increasing coverage without corresponding operational overhead.
Operational teams appreciate the practicality: alerts arrive directly on phones; units can be swapped rapidly; and there’s no specialist software to manage. By building on BT’s existing enclosures and using ubiquitous GSM/SMS, the TAD-220 keeps ongoing costs predictable while maintaining high responsiveness in the field.