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Author Topic: Amiga and Cell phone  (Read 4455 times)

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Offline Floid

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Re: Amiga and Cell phone
« on: August 16, 2003, 06:13:47 PM »
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downix wrote:
A Cell Phone's radio signals can cause chip damage.  I've managed to damage more than 1 machine due to bad positioning of a CB rig before, and CB's don't pump out as much freq as a cell phone.
'Frequency?'  CBs generally run with much, much more power than a cellphone.  In turn, cellphones run at a much higher frequency, but usually at milliwatt levels.

Anyhow, depends on a lot of factors.  Long wires (speaker cables, etc) can act as antennas, and if near a transmitter, could have enough current induced to crash a machine or even fry components if you're unlucky enough.  For a GHz cellphone signal, chip leads and the like could have the same effect, and *maybe* the properties of the signal could make it more prone to penetration, interference with actual board-level signals, etc.  (The reason those walkie-talkies were taking out the 1200 is probably because they ran at a relatively low frequency similar to those used in the 1200 itself - instead of creating, say, some ripple on a signal, they were probably 'close enough' to cause bit errors, maybe some sort of clock/timing skew... or, again, just powerful enough to ram enough induced current in the wrong directions.)

It's certainly possible, of course; a lot depends on the 'sensitivity' of your equipment. (an Amiga, for instance, obviously has to run tighter tolerances all around than a simple 8086 clone board built by sweatshop labor in the '80s, or most modern commodity chips/boards, following the same principles - whether 'designed in' or 'evolutionary' - to allow for high manufacturing and assembly yields.)

Even running 100-133MHz machines near a high-powered 144MHz transceiver, I've managed to never see a problem.  The line noise a 'HF'/'shortwave' (3-30MHz) transmitter can cause to a 300 baud modem, on the other hand...

Cellphones need to be turned off in a medical environment not only for the minor risk of inducing some sort of crash in their controllers, but because the sensing equipment (EEGs, heart monitor electrodes, etc) might possibly be sampling for faint biological signals at such frequencies, and because some of the equipment itself probably communicates on related bands, or uses related RF-sensitive circuits for things like signal amplification, etc. (Remember, the 2.4GHz "ISM" band 802.11b runs in is "Industrial, Scientific, and Medical.")

When in doubt, leave your case/shielding on, and don't go using your phone's antenna as a logic probe.
 

Offline Floid

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Re: Amiga and Cell phone
« Reply #1 on: August 16, 2003, 08:46:10 PM »
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_LinchpiN_ wrote:
Dunno about cellphones,, UK legal CB pushes out 4watt on the 27mhz wavelenghth ( i think its 11mtr band FM)
Some info on US regulations here.  http://home.att.net/~wizardoz/cbmw/fccrules.html  As far as I know, most sets are AM on all 40 channels; a few have the SSB option.  It's long since gone to the dogs here, and plenty of hardcore users see nothing wrong with illegal amplifiers and such things.  Some truckstops even run advertising tape beacons and the like.

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Pointless info

With reguards to using your cell phone as a modem, you would just need a phone with a modem in (duhh) like the nokia 7110, a data cable capable of transfering internet signals (or Infra red, doubt amiga uses that tho), and basically install the phone as a modem with a driver.

Hope this helps, i do it on my lappy often.
Yeah, I never got around to noting that.  Unless you have pure analog service, you're going to want to/have to do it this way; the phone 'modem' (whether inbuilt, as on the Nokia, or external, as available for some Samsungs) takes the bitstream directly, and converts it to something almost but not entirely unlike a 'regular' modem signal, which traverses the digital network until it gets to the endpoint designed to deal with such.  (In other words, I think you'll be stuck dialing your phone provider's ISP, though Europe might have more competition in that space.)

Atop that link should run regular PPP, which any Amiga IP stack with PPP support should be able to deal with.

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Some of the new 'personal hub' phones can expose what might be a 'raw' IP interface over Bluetooth or 802.11b.  The latter, at least, should connect 'easily' to an ethernetted Amiga through use of a WET11 or something.  Maybe.