This can include observation from a distance by means of electronic equipment ( such as CCTV cameras ) , or interception of electronically transmitted information ( such as Internet traffic or phone calls ) ; and it can include simple , relatively no - or low-technology methods such as human intelligence agents and postal interception .
This may include observation from a distance by means of electronic equipment ( such as CCTV cameras ) , or interception of electronically transmitted information ( such as internet traffic or phone calls ) . Surveillance may include simple , relatively low-technology methods such as human intelligence agents and postal interception .