Pretty much everybody who's ever watched a television commercial lately has seen those that depict an anti-intrusion alarm system.

The theme is forced entry into a home, with a loud alarm going off at one point or another.

However, these systems don't feature video surveillance, which might have given someone more warning.

That's why knowing something about these systems – including their BNC connectors – can be important, especially when a system is going to be purchased.

Knowing something about cameras, recorders, monitors and the cables that run between them to connect them to each other might be necessary when trying to decide how durable or sturdy the system needs to be.

Consider the cables, for one, and how strong their physical connection might be to various pieces of equipment. These connectors come in a couple of different varieties.

The connector spoken of in the introduction – a BNC (Bayonet-Neill Concelman) connector – is usually used in a wireless security camera system that makes use of RF ("radio frequency") to send images captured by the security cameras to monitors and recording equipment.

It's a good method for terminating the coaxial cable that's used in many RF signal connection uses, by the way.

Where the BNC connector might be seen in this regard is as an alternative to RCA connectors.

These are the ones with the red, white and yellow plugs at their ends and which insert into tiny holes in the back or along the side of composite video equipment such as a DVD player and the like. Almost everybody's familiar with an RCA plug.

But the downside to those plugs is that they can be pulled out of video equipment such as video security cameras relatively easily or inadvertently, thereby preventing the RF signal equipment from sending their signals to the receiver equipment in the system.

For example, the threaded BNC connector (sometimes known as a TNC), can be screwed down and locked from the male connector to the female connector and vice versa, though the bayonet (the "B" in the BNC) lock is usually sufficient.

Using this sort of connector can be an effective and inexpensive way to keep cables connected to their equipment in even the most "shaky" of environments (high winds, extreme movement).

It ensures no dropping of video images if cables happen to be pulled from their RF signal sources, for one and it's also a relatively inexpensive upgrade from RCA plugs.

All isn't golden with a BNC connector though, because the same things that make them attractive (their locking ability, for one) can make them more difficult to easily move around, especially if the bayonet lock becomes damaged or pinched or crimped excessively.

The cable would then need to be cut and a new connector affixed. And they're still more expensive than standard coaxial cable connectors.

Still, BNCs are the standard for wireless security camera systems and any problems they present are usually minor.

Check with the installation professional as to what cabling and connectors he intends to use. Some money can be saved by going with RCA plugs, but for those who want to make sure their cameras continue to transmit because they won't suffer cable disconnection, BNC connectors may be the most appropriate choice.