I have read that the ISM band is the same in most countries around the
world. A person asked me why this was the case and I wasn't sure. My
guess is that since devices using this unlicensed spectrum are often
mobile devices or in mobile vehicles (e.g., planes, cars, etc.), a
device could seriously interrupt communications when going from one
country to another if the ISM standards were not the same. Is this
somewhat correct?

Thanks,

Kensei

In article .com,
wrote:
I have read that the ISM band is the same in most countries around the
world. A person asked me why this was the case and I wasn't sure. My

The spectrum allocation is set up the the ITU, part of the United
Nations. Every 10 years or so they have a meeting to change the
allocations.

If you're curious, for the US, the chart is published in the FCC
regulations. Title 47 Code of Federal Regulations, Part 2. It's
about 100 pages or so. Plus footnotes. From 9 kHz to 400 GHz.

ISM stands for Industrial/Scientific/Medical. In the US this is
Part 18 of the regulations. You're not allowed to communicate or
broadcast with ISM equipment, but you are allowed unlimited power.
It's for glue curing machines, medical diathermy heaters, microwave
ovens and the like.

guess is that since devices using this unlicensed spectrum are often
mobile devices or in mobile vehicles (e.g., planes, cars, etc.), a
device could seriously interrupt communications when going from one
country to another if the ISM standards were not the same. Is this
somewhat correct?

Stuff that does communicate information isn't ISM equipment. Bands
can be used for more than one thing. As the unlimited power of the
industrial uses of these bands makes them a junkyard for serious
purposes, they're also allowed for low power unlicensed use. In the
US this is under Part 15 of the regulations.

Last I checked (read the footnotes for that frequency in the allocation
chart), the 915 MHz band had 5 (or 6?) different users, some with priority
over others. Off the top of my head, it was

Government Radiolocation (ie. military radar)
Commercial Radiolocation
ISM
Amateur Radio
License Free

License free is at the bottom of the list, that's why equipment has
the little sticker (or a note in TFM) about users having to accept
any interference from licensed users.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

Kensei

wrote in message
ups.com...
I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

Kensei


Because the ISM equipment is shipped around the world and the interference
from such equipment can cause interference which can also propagate around
the world.

Consider 27MHz, this is an ISM band and diathermy machines make a hell of a
racket. When propagation is good, only a few watts is required for
international communications. These machines leak RF and it can cause RF
interference around the world, that is, unless the rest of the world is also
using the same frequency.

It reduces the cost of manufacture if all the medical machines use the same
frequency bands instead of having to redesign them to suit each country.
Same applies to industrial and scientific applications. It's called band
planning.

Brad.

In article . com,
wrote:
I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

I suppose you could see if you could find some sort of report or
proceedings from the treaty meeting that set up the bands as they
are. Probably in the 1950s, but it could have been earlier.

I'd go with "just because". Or the common sense reason: if you can
radiate unlimited power...

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

Thanks. That's basically what I thought. Also, some very mobile
equipment which are not ISM equipment but use this band (e.g., laptops
running some version of 802.11) could also interfere with critical
communications in another country if ISM were not standardized. But, as
you have pointed out, the ISM band was originally developed for the use
of ISM equipment so they could be shipped and moved around the world.
It seems to me the later use of this band by other equipment (e.g.,
mobile laptops) was done to capitalize on the fact that no license is
needed to broadcast in this band and broadcasts will not interfere with
other critical communications when moving from country to country.

Thanks,

Jeff