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From: clewis@ecicrl.UUCP (Chris Lewis)
Newsgroups: news.sysadmin,news.admin
Subject: Re: i2ack request for news/email supply connection
Message-ID: <198@ecicrl.UUCP>
Date: 26 Jan 89 16:22:04 GMT
References: <102@i2ack.UUCP> <9198@cit-vax.Caltech.Edu> <56046@pyramid.pyramid.com> <332@microsoft.UUCP> <8820@alice.UUCP>
Reply-To: clewis@ecicrl.UUCP (Chris Lewis)
Organization: Elegant Communications Inc. (CRL Division)
Lines: 47

Regarding people asking about the legality of various modems in Europe.

People have to remember that each country usually has its own electrical
codes and standards.  The reason why a particular modem isn't legal in
some country but is legal in others often has nothing to do with 
"monopolistic" PTT's per-se.  It could be a safety requirement.  It
could also be that North American style modems simply wouldn't work there
even if they were legal!

For example, there is a standard dictating how much electrical isolation
must be provided in the DAA (the thing that connects the modem to the
telephone line).  In the US, I think it's around 1,000 volts.  In Canada
it's slightly higher.  In Britain it's four times that.
Most modems made in North America don't meet the British standards in
this respect and are illegal there.  There are even a few modems made in the 
US which aren't (strictly speaking) legal in Canada.  

Or, the telephone system is working on different impedances - the modem
would not only not work, but could also short half the network out.

Or it's digital.

Or requires different filtration.

And so on.

Some modem manufacturers meet other country's standards.  Other 
manufacturers make different versions for foreign countries.  Many
manufacturers think "all the world's american" and don't think that 
the market for foreign-standard-conforming equipment is big enough.
And some countries insist on PTT supplied devices.  Sigh.  Fortunately
ours deregulated in that respect at least 15 years ago.  Also fortunately, 
since we're the US's biggest trading partner and our codes aren't all that much
tougher, most manufacturers worth caring about in the USA meet CSA 
standards too.  Don't forget that there's one hell of a lot of stuff
manufactured in the Far East that's illegal just about everywhere...

I wouldn't blindly assume that restrictions on modems are due to monopoly.
Nor are the standards themselves - each country has different tradeoffs on
what is a justifiable risk, and are often working under different environments
(eg: 240V mains in Britain).  Our CSA is tougher than US UL.  BTT (Britain)
is overall much tougher than CSA.  Etc.
-- 
Chris Lewis, Markham, Ontario, Canada
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