imagine the amount of intel they could get by simply using an IMSI-catcher at the jail instead?

that being said they could just look at jamming signals instead of doing all this every month or so.

Related trivia:

There are dogs trained to sniff out cell phones in prisons. They key off the batteries.

Some prisons use so-called Managed Access Systems to control contraband cell phone usage. These mini-cell-sites have a database of allowed phones that can make calls, while all others are black holed such that they can only dial 911. This enables the prison to avoid jamming emergency calls from citizens who might otherwise fall under the umbrella of jammers or similar active blocking means. To avoid MAS systems, inmates construct directional dish-like enclosures out of foil or similar materials to try and block the local MAS site and get their contraband phone to attach to a normal cell site outside the wire.

Note the bottom photo in the article illustrates anti-helicopter poles and cables. These are also present at other sensitive sites subject to heliborne assault, like Germany's Stammheim Prison, certain US nuclear weapons-related facilities (e.g. LLNL Superblock), etc.

> The French supplier of the devices – a company called Oportik – has been stopped from trading and three staff members arrested. It is believed to have sold about 5,000 of the phones

> While they are themselves perfectly legal in France, it is a crime to supply a prisoner with a phone.

Is the allegation that the three staff knowingly supplied to prisoners or what's the story with those arrests?

an example image depicts a phone about same size as a cigarette lighter, smooth n rouned all over. i have suspicions where these are hidden.

https://ichef.bbci.co.uk/news/800/cpsprodpb/7d41/live/82aafd...

"According to Le Monde newspaper, the devices were nicknamed "suppositories" by prison inmates because of their ease of concealment."