Comments on: Remote Control Dell Optiplex Hack

Question: Remote Control Dell Optiplex Hack

billy_the_punk — Tue, 08 Aug 2006 13:06:58 -0800

Is there any truth to this rumor about the Dell Optiplex GX520, and if so, why?

At my office we just recieved a brand new Dell Optiplex GX520. As expected, (this always happens before my holidays), it started acting wacky. Symptoms included spontanious restarting, freezing, inability to turn on with the printer also turned on, and siezing up during backup. In my research efforts to narrow down the problem I came across this.

Many people in our office use Blackberries, and at the time I was wearing a wireless headset for the phones. I wasn't really given a chance to test the theory directly due to my cell phone being at home.
When the Dell tech came in to replace the motherboard I mentioned it to him, and he laughed at me. Am I as gullible as he thinks, or is the pending all-office-switch to these new models a genuine concern?

By: raedyn

raedyn — Tue, 08 Aug 2006 13:30:05 -0800

I haven't had that problem with the Optiplex GX620 that's standard issue in our office, and cell phones are in regular use here.

Note: I have never specifically tried sending text messages from one phone to another when they're both in close proximity to the PC, and this is a 620, rather than a 520. But still.

By: suedehead

suedehead — Tue, 08 Aug 2006 14:03:51 -0800

I doubt it, as the faraday cages would probably take care of interference, no?

In any case, I just tried it with two nearby gx520s. I sent a SMS to my cellphone from an online site, putting the phone where the phone in the video was placed. Nothing happened.

By: lemonfridge

lemonfridge — Tue, 08 Aug 2006 14:18:42 -0800

My Sony K750i plays merry hell with my iPod Video when i receive a txt. Sometimes volume goes up, sometimes volume goes down.
phones can do funny things to electronics. i wouldnt say its the cause of the problems you're experiencing however.

By: the ghost of Ken Lay

the ghost of Ken Lay — Tue, 08 Aug 2006 15:32:07 -0800

inability to turn on with the printer also turned on

That screams problem with your AC outlet or possibly the power supply. It might even be tripping the fuse on the power strip.

By: tomierna

tomierna — Tue, 08 Aug 2006 15:34:47 -0800

My business partner has a couple of LaCie Firewire drives which will power down if he receives a text message or phone call when his phone is too close to them.

His phone is a Nokia 6630, I think.

EMI can do some wacky things to computers, so it wouldn't surprise me if a particular phone combined with a particular revision of a computer might trip some circuit up enough to shut down or reboot it.

By: joeblough

joeblough — Tue, 08 Aug 2006 20:19:31 -0800

man, someone needs to report all of these companies to the FCC. this isnt supposed to happen, and all consumer products are supppsed to be qualified in approved labs for EMC before sale.

By: five fresh fish

five fresh fish — Tue, 08 Aug 2006 21:16:16 -0800

IIRC the rules say nothing about how the device must handle receiving interference. It's all about how much the RF the device puts out.

By: Chuckles

Chuckles — Tue, 08 Aug 2006 22:20:14 -0800

As far as I know the basic standards for consumer electronics are all about broadcasting interference into the AC by conduction and into the air by radiation (which depends on jurisdiction).

Problems when receiving interference are due to electromagnetic susceptibility (EMS). This article looks like it might be interesting, Electromagnetic compatibility, interference, and susceptibility in EET programs.

It is always possible that the design has a problem, making it especially susceptible.. Did the new motherboard fix it? If it did, you have nothing to worry about.

By: billy_the_punk

billy_the_punk — Wed, 09 Aug 2006 09:36:22 -0800

To answer your question Chuckles, no the new motherboard did not fix it. All problems were still present. Last I heard they were replacing more hardware parts, however as I am on vacation I am no longer in the loop (and unable to test with my phone unfortunately).

By: Chuckles

Chuckles — Wed, 09 Aug 2006 20:19:37 -0800

Well, that is pretty annoying. A design problem seems pretty unlikely, and a design problem related to EM susceptibility seems very unlikely.

As has been pointed out, the printer issue is unusual. The other problems are standard hardware troubleshooting issues: overheating, power supply, bad memory, bad video, etc.

I'd suggest trying to figure out what is going on with the printer, but since you are on vacation.. Just quit worrying and have some fun!

By: Chuckles

Chuckles — Wed, 09 Aug 2006 20:27:50 -0800

Ya, easy for me to say..

By: joeblough

joeblough — Sun, 13 Aug 2006 00:33:46 -0800

it would appear that title 47 only makes an advisory statement about susceptibility to EMI. that's strange, i thought that class B devices also had to accept a certain amount of EMI. maybe i'm looking at the wrong subpart.

TITLE 47--TELECOMMUNICATION

CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION

PART 15--RADIO FREQUENCY DEVICES--Table of Contents

Subpart A--General

Sec. 15.17 Susceptibility to interference.

(a) Parties responsible for equipment compliance are advised to consider the proximity and the high power of non-Government licensed radio stations, such as broadcast, amateur, land mobile, and non-geostationary mobile satellite feeder link earth stations, and of U.S. Government radio stations, which could include high-powered radar systems, when choosing operating frequencies during the design of their equipment so as to reduce the susceptibility for receiving harmful interference. Information on non-Government use of the spectrum can be obtained by consulting the Table of Frequency Allocations in Sec. 2.106 of this chapter.