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Image: RON
Across South Africa, concern is growing that Pollsmoor Prison, one of the country’s most notorious correctional facilities, is being used not just to confine criminals, but to host criminal operations.
In recent weeks, Cape Town Mayor Geordin Hill-Lewis has urged the deployment of sophisticated signal-blocking technology inside Pollsmoor, arguing that inmates are using contraband mobile phones to coordinate extortion, gang violence, and other illicit behaviour from within prison walls.
This push is part of a broader plan: the Minister of Correctional Services, Pieter Groenewald, has already earmarked five correctional facilities, Pollsmoor among them, for a pilot project to trial cellphone signal-blocking tech, with full implementation expected by the end of the year.
What exactly is “signal-blocking” in this context? There are a few different technical strategies in use or under development internationally and in South Africa, with varying trade-offs.
Signal jammers / blockers: These devices emit radio signals that clash with or overpower mobile phone signals (2G, 3G, 4G, and increasingly 5G). By doing so, they prevent phones in the affected area from being able to connect to cell towers. Some solutions also include WiFi or Bluetooth in the blocked bands. For example, companies such as Stratign advertise “prison jammers” capable of handling multiple frequency bands, sometimes even networked and managed remotely.
Detection systems & remote monitoring: Instead of outright jamming, or as a complement to it, some correctional systems use detection technology. These systems monitor unauthorised phone or signal use (including WiFi, Bluetooth), triangulate or locate the devices inside the facility, and alert guards or control rooms. An example is the Unify DETECT solution, which can pinpoint the location of a mobile used inside a prison cell, sometimes down to the individual cell.
These technical choices each come with implications for cost, infrastructure, maintenance, and oversight.
Jamming tends to require more continuous power, stricter safety controls (since you are interfering with radio waves), and careful calibration to avoid disrupting permitted or emergency communications.
Detection is less disruptive but can require dense sensor networks and constant monitoring of data.
While the technological promise is real, it does not sit in a legal vacuum.
According to South Africa’s telecommunications regulator, the Independent Communications Authority of SA (ICASA), use of devices that jam cellular signals is illegal, at least for private or public entities outside of explicit authorisation.
This position is grounded in Government Gazette 24123 (November 2002), which makes “mobile telephone blocking devices” unauthorised under general law.
Thus, even though political leaders such as Hill-Lewis and Minister Groenewald are calling for pilot installation, they will need to square these calls with existing legal prohibitions.
One route may be to obtain special authorisation, regulatory amendments, or court orders that allow for controlled use within correctional facilities.
The driving force behind the push is not speculative: according to public statements, Pollsmoor inmates are reportedly using phones to direct extortion threats—even pulling contractors off work sites via threats from inside prison.
The Mayor has offered the City of Cape Town’s “full support” for the pilot: intelligence-sharing, technical and logistical assistance, and raising public awareness.
If successful, the pilot project could set a precedent for broader roll-outs, perhaps across the more than 200 correctional centres in South Africa. But success depends on navigating:
Regulatory approval for jammers or signal blocking,
Integration with existing infrastructure: prisons would need to avoid interference with security radios, emergency services, or legitimate internal communication;
Maintenance, monitoring, and costs, including energy, physical security of the devices, and oversight;
Ensuring human rights and due process, e.g. clearly defining what communications are blocked, when, and ensuring accountability so that misuse or overreach doesn’t occur.