Hack verses intrude. I guess that's really the question. Hacking analog telephone lines would have to be done via connected equipment as the analog telephone company lines are not readily available to computer hacking. T1 and ISDN lines are extremely vulnerable to hacking, provided the hacker has the appropriate equipment.
Intrusion, on the other hand, is quite easy on analog lines. One need not even be in the building where the lines terminate to "butt" into the line. I don't think this is considered hacking, per se, as opposed to computer hacking. T1 and ISDN are nearly impossible to hack, unless, of course, the hacker gets into the telephone system via the T1 or ISDN and finds a path into the system. Technically, the T1 or ISDN is not hacked, but, rather, the phone system is. If the hacker has a mux/demux box, which is available, the hacker can then hack an in service T1 or ISDN. However, this would have to be an onsite hack and would not be discreet.
Let's face it, if someone wants to be malicious, they can be and it's just a matter of degrees as to difficulty. Generally speaking, a T1 or ISDN will offer more security to intrusion than an analog line.
Rcaman
