Paul Asks:
PA>You said in your note about the FCC that if you kept the crystal down under
PA>1.7MHz, then you don't have to be tested for radiated emmissions.  What do
PA>you test for then?

My understanding is that if you are *battery powered*, unintentional
radiator,
then you are exempt from FCC verification.

reference: FCC 47 CFR edition 10-1-93  subpart B - unintentional
radiators -
section 15.103 (exempted items) item H - "Devices in which both the
highest frequency generated
and the highest frequency used are less than 1.705MHz and which do not
operate from the AC
power lines or contain provisions for operation while connected to the
AC power lines.  Digital devices
that include, ..., AC adaptors, ...,do not fall under this exemption."

Other exemptions include: anything for use in a motor vehicle or
airplane, devices used for industrial,
commercial, or medical test equipment.  devices used in appliances.
Devices consuming less than 6 nW of power.

But if you generate enough RF noise to mess up someone's TV or radio
reception
then the FCC will probably want to talk to you.
PA>Of course, I DO want to use a wall-wart to power my device,
PA>I MAY have to get that tested anyway.

I don't know what happens when you connect to a wall wart.  You will
have to ask
someone at the FCC.  My experience is that you need to ask several
testing labs to get a concensus.
I asked 5 labs, 2 said no radiated testing if clocked under 1.706MHz.
When I told the other three, they said they would get back to me,
Those that did
finally agreed.
So.. you will have to ask around to see what happens with a wart,
Please let us know the answer if you ever find it. (Statement above
seems to say it could be trouble)

PA>But, staying under 1.7MHz may save me
PA>bunch of bucks - right?

Again, my understanding is less than 1.7MHz - no radiated test
which saves at least $700.
But you may still need conducted emmisions test.
That is the part I am unsure of in the case of a wall wart.
Be sure to get several bids,  conducted test is less expensive, but you
may get hit with minimum charge.
Ask if they can fit you in on a time available basis, meaning they will
do it whenever they get a small vacancy at
their site.

Of course, NONE of this has to do with UL, CUL, VDE, ETL, .....
approval.
that is a whole 'nother deal.

Also if you connect to the phone network, that opens a bigger can of
worms.

Hope this helps,  Gary Skinner

A couple of more numbers:
FCC  301-725-1585 x229  Ed Givens

TUV labs,  Boulder CO  449-4165