In recent years prison information leaked seriously

That would mean every smuggled phone in the facility would be quickly identified. In addition, it would be relatively easy to create a list of permitted phones (owned by guards, office staff etc) and pass calls from those devices through to the communications networks. Alternately, we would have to ask exactly why it was that a guard needed a phone while on duty.
Mobile phones were seized from Block 1,2,3,4 and High-Security block 1. A jammer had been installed in the prison premises two months back. Last year, there were allegedly 72 mobile phone cases registered, while the number is already at 64 this year.
“During the raid, we seized mobile phones from toilets, rain water harvesting points and even shoes,” a prison official told TNIE. “Someone had torn the back of a slipper, inserted a phone and pasted it again. Mostly, inmates hide phones in awkward or unexceptional places that are being used daily.”
Repeat offenders are allegedly the most likely to possess phones as they have visited the prison multiple times and are aware of how to conceal and use the device.
Even better, this method would permit the identification of those being called from the gaol, especially if the existence of the base station was kept very quiet.
But Talisay City Mayor Eduardo Gullas said there is no need to install a cellpone jammer since anomalies can be prevented if jail rules are strictly implemented.
Gullas added that purchasing a jamming device is an additional expense of the city with funds that can be utilized for other purposes.