Metallic mesh in external ports area...what's its purpose?

[Prevost]

I see within my computer, between the external ports and the rear panel, what to my eyes is a kind of metallic mesh. Is it that? What is the reason for this here? How can it be cut?

[rocky_raher]

Most likely it's put there to reduce the amount of radio-frequency radiation that would otherwise leak out of the computer's metal case, and cause interference with nearby radios or televisions.

[Prevost]

Do all computers have it???

[Dave Beauvais]

Not all, but most "store-bought" PCs do. Generally home-built PCs don't have the stuff, but some higher-end motherboards include it as part of the I/O port shield. Rocky is right... it's an RF-blocking material to help reduce interference from all the stuff going on inside the case.

[Prevost]

Generally home-built PCs don't have the stuff
I almost guessed this...

Now, does having it or not make an actual difference in the amount of interference caused to other devices ?

[Dave Beauvais]

Only one machine I've built has come with this material, but I've never experienced any problems with those that don't have it. (i.e., TV or radio interference, etc.) I'm sure Dell, HP, and other manufacturers have to include it to comply with some kind of FCC regulation. :)

[Prevost]

What could be the range of computer's RF signals at which those can reach other appliances causing interference ?

I think we should fight for having that kind of shield in our cell phones...I use to have mine about one foot away from my monitor and I notice a call is coming in first thru my monitor than by the ringing of the phone!

[Dave Beauvais]

Heh... at my last job we had Nextel phones and I could always tell when it was about to ring or I was getting a direct connect call because any computer speakers that were nearby would make a static "tapping" noise. The noise would persist as long as the phone was in use. RF is a fact of life these days. Every piece of electronics generates RF, from a digital watch, to a compact fluorescent light, to computers; it's just that some things are better shielded than others to prevent its leakage or to block it from entering. I have a lamp with one of those spiral-shaped compact fluorescent light bulbs that doesn't get along well with the TV that's next to it. That's about the only thing I've got that I know is causing some RF-related problems. Turning the lamp off or moving it about three inches or more away from the TV solves the problem.

As an aside, all these cool transparent acrylic computer cases that are all the rage among case modders are not FCC compliant in the least. Typical computer cases rely on the metal inside or on the outside of the case to absorb and block RF. The clear plastic cases just let it all radiate out in all directions. Add in neon tubes, fancy illuminated fans, and all the other goodies that modders add, and you have a little RF factory just waiting to mess with nearby TVs, radios, cordless phones, etc. The good news is that nothing much is really affected by RF interference these days. If anything, the computer in the plastic case is likely to be more affected by RF entering it from other sources than the things around it being affected by its RF leakage.