Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!uw-june!uw-entropy!dataio!pilchuck!del
From: del@Data-IO.COM (Erik Lindberg)
Newsgroups: comp.dcom.modems
Subject: Need 9600 for severe noise environment
Message-ID: <872@pilchuck.Data-IO.COM>
Date: 21 Apr 88 18:45:51 GMT
Organization: Data I/O Corporation; Redmond, WA
Lines: 29

I am in the position of having to come up with a recommendation for a modem
to Taiwan, R.O.C., and would like to use a 9600 baud modem if possible.
The line noise to that little country is simply astonishing, and trying to
relate specifications and test results to reality is difficult. On voice
communications it is necessary to raise your voice to be heard above the
background noise given the weak signal strength (faint voice).
     Currently, they (Taiwan) are using a SmarTeam 2400 baud modem to
connect with my system (Kirkland, WA) using a Hayes 2400. Connections at
2400 baud can be made if the moon is full and the conjunction of Mars,
Venus, and the Jupiter form an Isosceles triangle. :-) Connections at 1200
can usually be made given two or three attempts.
     I had previously thought to recommend a Trailblazer, which (theoretically)
would fall back in 100 baud increments to get the maximum throughput on the
line. I read in the recent PC Rag review, however, that their TB modem gave
up entirely at -27db signal/noise ratio. This compares with the SmartTeam
2400 signal/noise ratio performance of about -28db at 2400 baud (doesn't
work) and -15db at 1200 baud (works). These figures quoted from the April 26,
1988 and May 12, 1987 PC magazine issues.
     As you can see, the -27 db figure for the TB is dangerously close to the
SmarTeam at 2400, which failes miserably. The USR HST is only marginally
better than that (2db). The only modems that had sterling performance down
to -19db s/n do not support 1200/2400 baud. That is fine for Taiwan since they
can just switch modems, but not for me since I must support a dial up line
and cannot justify a dedicated line just for the one caller.
     Any suggestions, anyone?

-- 
del (Erik Lindberg) 
uw-beaver!tikal!pilchuck!del