Looking for continuous, encrypted central station alarm monitoring with line cut detection

[invalid@xxxxxxxxxxxx (Beachcomber)]

When I was installing Ademco Alarms in the late 70's, it was quite
common to install dedicated line,dc reversing relay, and central
station monitoring.  This was in the days when the central alarm
monitoring station was in the local area of the town itself, or
sometimes even at the police station.  One of these panels was briefly
featured in the old Clint Eastwood movie "Thunderbolt and Lightfoot".
It had a DC ammeter and a 'line trouble' lamp for each account module.

As I return to to the alarm business these days, times have certainly
changed.  The dedicated lines seem to not be used quite as often
(maybe because of the expense and complexity in dealing with the phone
co?) Apparently, POTS dialers are used in most alarms and almost all
police departments require permits, separate alarm monitoring
companies, etc.

Here's my question -  Back in the 70's, Admeco had a super-secure and
encrypted central station that would alert the attendant to line cuts
and could not be defeated by the spoofing techniques that Jim Belushi
used in the movie "Thief" (i.e. inserting DC power supplies in the
telephone/alarm lines).

Is there an equivalent of this system today?   That is...

1.  Requires continuous duplex communications over a dedicated phone
line.
2.  Passes encrypted and verified data back and forth to minimize
intruder 'spoofing' attempts.
3.  In addition to alarm notification, it alerts the operator to line
cuts or when someone is otherwise tampering with the phone line.

When I search for Ademco on the Internet these days, I get redirected
to Honeywell sites.  Did Honeywell buy Ademco?

Any information greatly appreciated!

Beachcomber