caserta@athena.mit.edu (Francesco Caserta) (02/21/91)
I was planning to buy a 9600 bps modem (and a fax machine) here in US and bring it back in Italy, when I remembered that I once read that for high speed modems ( >2400 bps ) the european standards differ from those in US. The problem doesn't seem to lie within the telephone lines, but just the adopted standards. Can anyone enlight me on this? You can either post on the net or e-mail me. Thanks a lot, Francesco Caserta
tnixon@hayes.uucp (02/22/91)
In article <1991Feb20.222435.25871@athena.mit.edu>, caserta@athena.mit.edu (Francesco Caserta) writes: > I was planning to buy a 9600 bps modem (and a fax machine) here in US > and bring it back in Italy, when I remembered that I once read that for > high speed modems ( >2400 bps ) the european standards differ from > those in US. The problem doesn't seem to lie within the telephone lines, > but just the adopted standards. Actually it is in the LOW SPEED standards (300 and 1200) that the USA differs from international. We generally use Bell 103 and 212, whereas the CCITT counterparts of V.21 and V.22. V.21 is not at all compatible with Bell 103 (uses entirely different frequencies); V.22 is, however, very close to Bell 212 and interworks well most of the time. In fact, most modems sold in the USA support both 212 and V.22 now, and many support both V.21 and Bell 103. At 2400bps, the whole world (basically) uses V.22bis, and V.32 at 9600. Likewise, Group 3 fax is the same everywhere. You biggest concern will not be with modulation schemes, but with power (Italy uses 240v 50Hz, the US uses 120v 60Hz), connectors (both the power and phone connectors are different, but you can probably get adapters), and the design of the phone line interface. Yes, it will probably WORK (everybody basically uses tip and ring), especially if you use DTMF (tone) dialing (which is CCITT standardized; pulse dialing is not). But you may get into trouble with the PTT there for connecting unapproved equipment. -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net