You can find out more about
V.34 modems and noise at www.swin.edu.au, Curt's High Speed
Modem FAQ, or Line Noise Testing Procedures.
Three factors determine connecting at 56kbps.
Your phone line must be capable
of supporting K56 speeds.
You must have a modem that matches the protocol used at the
ISP. Currently there are three formats. K56Flex, X2, and V.90.
The new ITU 56K modem standard is V.90 and this along with
K56Flex are formats we support.
You can find out more about 56K at www.56k.com, www.k56.com,
http://www.v90.com/, or http://808news.com/56k/.
A. Unexpected disconnects can plague any data communications
connection. Generally, there will always be an occasional
disconnect. After all, we are dealing with phone lines being
pushed to the limits with V.32, V.34 and now V.90 modems.
Phone lines were designed for voice, not for data transmission.
If you find that you are experiencing frequent or infrequent
disconnects with your connection to Internet Pathway, the
following information may assist you in troubleshooting this
situation.
Inactivity Timeout
Internet Pathway has a 60
minute timeout on idle connections. A 60 minute timeout means
we will drop the connection after 60 minutes of there is no
network activity (no packets sent or received) on your PPP
connection.
While this may be obvious to many who are reading this, it's
a good idea to keep in mind that "no activity" doesn't
mean that you're not doing anything. You could be composing
an email message, or reading a web page; it's even possible
to go from one web page to another and have them all be in
your local computer's memory cache. These would all equal
"no activity" on your network connection to Internet
Pathway and could result in a dropped connection.
One way to ensure that "no
activity" is not the cause of disconnects is set keep
an email client like Eudora or Netsacpe open during all sessions
and set that email program to check for mail every 15 minutes.
But if you're getting a lot
more than the occasional disconnect, something is wrong and
you should methodically follow the steps below.
Call Waiting
If you have the call waiting
feature from BellSouth, your connection can be interrupted
if you receive a call while online. Disable "Call Waiting"
by dialing *70, before the accces number. This disables call
waiting for the duration of the call and is automatically
re-enabled when you hang up. This is an option with Windows
95 dial-up networking.
Line Noise and
Frequent Disconnects
Frequent disconnects may
be tied to specific line problems. Even if other connections
to other providers or BBS's in the area are stable, the specific
connection made from your locale to ours can be problematic.
These problems may be represented as occasional line bursts
that drop connections, or consistent line noise that result
in lost connections due to a modem's inability to deal with
the line conditions. Some modem brands, such as US Robotics
products, have line diagnostics that can be employed after
a disconnect to determine the cause of the drop. It may be
helpful to consult your manual to see if this feature is available.
A modem's ability to deal with line noise can make a world
of difference. Most modems will 'train down' to slower speeds
as line conditions worsen. Some 28.8 modems have been known
to have a 'spiraling death' syndrome, where they are unable
to 'train up' to higher speeds when conditions improve. These
speed negotiation may be transparent to the user of the modem.
At best, the user may simply notice that speeds become slower
and slower as time goes by. Frequent disconnects after similar
periods of time (i.e. every five minutes or so) can be symptoms
of this problem. Contact your modem manufacterer to obtain
the latest version of software (or 'firmware' in most cases)
for your modem. Many manufacterer's ship these upgrades for
free.
Line Noise and
Infrequent Disconnects
Infrequent disconnects may
reflect a temporary change in your connection. Weather conditions
can cause temporary changes in line conditions. Besides the
obvious physical damage due to fallen tress, etc., studies
have shown that excessive rain can cause increased line noise.
Physical work, like construction or new line installation,
can cause Bell South to temporary reroute line paths, perhaps
through a noisier switch. Lowering your baud rate temporarily
may allow your modem to 'weather' these changes in line condition
changes.
Line Noise and
Lowering Speed
Lowering your baud can accomplish
a few things with regard to line noise. A lower rate can force
your modem to switch to a different protocol (i.e. 19200 will
force a 28.8K modem to use the v.32 protocol which does not
renegotiate line speeds except in extreme conditions.) Secondly,
slower speeds much less succeptable to line noise. In the
"old days" when 2400 was screaming fast and there
was no error correction, line noise was a huge problem. The
common solution was to slow down to 1200, because the protocol
was more than half as succeptable to line noise. Nowadays
we have error correction, and don't "see" the line
noise, but the same solution applies. 19.2K may be slower
than what your modem is capable of, but if using a slower
speed allows you to maintain connections during times of noisy
phone ciruits, then it is, ultimately, much faster.
