Can anyone give me some insight as to the how to's of compromising a monitored alarm system by attacking the telephone line? Or a idea of where to look for this type of info?

Do these systems monitor if the line is cut? Anyone?

I think some do, but I don't know..

I also know some monitored systems don't use telephone lines anymore, because of the propensity of said lines to be cut.

They use radio contact instead.

You should really find out what company runs the alarm system, and then you'll have some idea of the specs and how to counter them

No one uses total radio contact. The high-end systems for houses use it as backup if the phone lines are cut. Plus the transmitter runs on a battery in case the power it cut too. Some labs and businesses where security is critical will use only radio and the phone as backup.

Plus you could always try jamming the reciever to test for reaction.

But yeah, you need to supply a company and system before we could potentionally give you any ideas.

From my experience the system's I am talking about do not use any sort of radio communication nor is a transmitter (i.e. antenna ) used to back the system up. It utilizes the phone line only. This is for a business and if i were to suggest a couple security companies that are common they would be ADT, Brinks, scs communcations ect. I was told some time ago of a item called a black box although they may be wrong as to the name of this device that was instrumental in comporimising the monitored alarm system. This device was attached to the phone line in some fashion that would not interupt the integrity of the line then the line could be cut the security company none the wiser. I realize that there are many forms of line security some more advanced than others. Although the obvious rewards in potentialy being able to comprimise a banks security system this is not my goal as i am looking into the lower end security systems.

Most alarms are monitored by phone lines, but cutting them will trigger an alarm at the monitoring station. And the alarm is usually specific, like "Hey, someone's fucking with the phone lines!"

BTW, i used to work in monitoring station. Also, cutting power is no good either, alarms are usually on 12v backup. They usually have an alarm at the monitoring station signifying loss of constant power, also.