Method of and apparatus for surveying an area

Details Method of and apparatus for surveying an area Method of and apparatus for surveying an area

1975-12-16

1977-10-11

Caldwell, John W.

Communications: electrical

Systems

Call station

325 52, 340 38L, 325 29, G08B 1324

Patent

active

040538770

ABSTRACT:
A security system for surveying an area such as a prison or airport, the security system comprising three coaxial cables which are placed in the ground parallel to and spaced apart from each other, the center cable being provided with a modulated signal which is received by the outer two cables, and the received signal being caused to vary and trigger an alarm if there is an unauthorized movement in the surveyed area.

REFERENCES:
patent: 2971184 (1961-02-01), Pearson et al.
patent: 3031643 (1962-04-01), Sheftelman
patent: 3043952 (1962-07-01), Reid
patent: 3230518 (1966-01-01), Vassil et al.
patent: 3237105 (1966-02-01), Kalmus
patent: 3641569 (1972-02-01), Bushnell et al.
patent: 3668625 (1972-06-01), Wolf et al.
patent: 3750125 (1973-07-01), Ross et al.
patent: 3801976 (1974-04-01), Ross et al.

Affiliated with

Also associated with

Rating

Method of and apparatus for surveying an area does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of and apparatus for surveying an area, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of and apparatus for surveying an area will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-742180