jeff@upas.UUCP (05/06/87)
The problem of modem incompatability exists all over the world,
not just in Europe. I work for an IRC (International Record Carrier)
and part of my job is to make modems work all over the world.
The following are some of the problems I have run in to.
Most all of the world uses the ccitt standards for modems. The Bell
standards mean very little to someone in Australia trying to purchase
a modem. It's been my experience that the Bell 103 modems are not
compatible with the V.21 modems. Fortunately, you can usually get
a Bell 212 modem to talk to a V.22. The only reason they talk is
that the tones are within some limits of the modems.
It had been suggested by someone that Europeans should just plug
in any old modem and use it, as the phone companies could not keep
up with enforcing this. But it's not that easy. The companies that
sell modems in Europe (and other countries) must have their modems
approved and 'type accepted' by the (Government Run) Communications
Authorities. This approval is not easily obtained. It is a sad fact,
but most of these phone companies are SERIOUSLY concerned that some
equipment will blow-up the network.
In other cases, the communications authorities make it illegal
to own certain modems. For example, In Denmark, it is illegal to
own any full duplex modem of 1200bps or higher speed. If you wish
to use these modems, you must lease them from Danish Telecom.
The modem that You lease is a Racal Vadic VA2422S. Manufactured
in the USA, but not available in the USA. It took me 2 1/2 months
to get one for my evaluation. Although it is advertised as Hayes
compatible (like most compatibles), it is not. I am now re-writing
some software so we may use these modems legally in Denmark.
In some cases (this time in Australia), if the modem you wish to use
is Not approved, but approval has been applied for, they will allow you
to use the modem, as long as a LIU (Line Isolation Unit) is connected
between the modem and telco. The LIU in Australia does two things, it
keeps the modem from "blowing up" the phone network, and it causes the
modem to not work. Most of the time, you have to use the modem without
the LIU (strictly illegal) in order to make them work.
In Japan, the modems you are allowed to use are manufactured in Japan
with instructions printed only in Japanese. So here, you need someone
to translate.
There is one method of overcoming the incompatability problems. That is
to buy your modems in the USA (usually cost less too) and export them
to the country you wish to use them. Unfortunately, there are other
problems. For one, exporting most computer equipment to foreign countries
can lead to all kinds of problems. If you have to get DOD (Department Of
Defense) approval, it can take as long as six months. If you try to export
without the proper license/forms, your shipment can be seized, and you fined.
I've heard rumor though, that modems below 9600 baud can be shipped
anywhere in the world without export license. Guess they think it's all
old technology.
If you do successfully get your modem exported, then you need to hope it
will work in that country. It is assumed you ordered your modem to use the
power available in that country. Because of FCC regualtions, all modems
purchased for use in the USA are factory set to transmit at a particular
level. Usually around -9 or -10 dbm. Many foreign phone networks,
such as in Singapore, require a hotter signal. Unfortunately, you cannot
change the transmit level on your Hayes modem. So now what do you do??
I can go on for days describing problems using modems in foreign countries,
but the point I'm really trying to make is that it's not just that easy.
In my opinion, the blame for incompatibilities lies with whoever
(probably AT&T) decided to use Bell 103/212 and not the CCITT standards
V.21 and V.22. I think we'll all find things easier as 2400 baud catches
on since the same V.21bis standard is being used.
Questions? Comments??
-Jeff (aka sysop at upas)
UUCP: seismo!nbires!isis!upas!{sysop,jeff}beattie@netxcom.UUCP (05/08/87)
I believe that bell 103/212 predate V.22 etc... -- ----------------------------------------------------------------------- Brian Beattie | Phone: (703)749-2365 NetExpress Communications, Inc. | uucp: seismo!sundc!netxcom!beattie 1953 Gallows Road, Suite 300 | Vienna,VA 22180 |