The radar detector industry has changed significantly in the past few years in direct response to the advances in the equipment being employed by police agencies nationwide. In order to understand the new technology, you must know how a radar detector works.
To make it easily understood, we will simplify the technology.
Basically, the speed gun emits a radio frequency that "bounces" off of your car and upon reaching back to the receiver tells the user how fast the object it bounced off of is moving at. The Laser type of gun does the same basic thing, using a laser beam rather than a radio frequency as in the regular one. The radar detector works by scanning the air for any radio frequencies or laser beams and alerts you if and when it detects one. Pretty simple stuff here.

The old style equipment that the police agencies used were always on and therefore were always emitting the radio frequency into the air. This was great for us because if the radar detector is on it will pick up the presence and warn you in plenty of time. Obviously this was not good for law enforcement agencies and therefore the advent of the newest technology had to make it harder to detect the signals. They accomplished this by making the units only emit a signal when the user "pulls a trigger". This will reduce the amount of time that the signal is emitted and therefore gives the radar detector less of a chance of "seeing" it.

Here is where the newest technology in radar detectors comes in.

Not only do the newest versions have front facing detectors, but they also have side and back. This allows for the radar detector to pick up the presence of a speed checking device from any angle. For instance, if there is one in use up a head and the signal is aimed at a vehicle other than yours, it will bounce off that vehicle at different angles. The newest technology in radar detectors is designed to pick up those "rogue" signals and alert you to the presence of the device.