Having
Modem Problems?
Slow
Connections
Getting
28.8 or 33.6 Connects
Depending
on your phone line quality, you may not achieve 28.8 connect speeds,
much less 33.6 connections. 26.4 connections are very common and
probably won't adversely affect throughput very much. You can also
try changing your modem's initialization string (see the section on
Initialization Strings for more information).
For
even more information about connect speeds, please see the following pages:
Lastly,
contact the phone company to see if there are any problems with your
phone line that can be corrected.
Initialization
Strings
Many
times, simply changing the initialization string that your modem
uses can improve your connection. Some basic strings to try are ATZ,
AT&F, or AT&F1. If you know the brand and model of your
modem, you should consult your modem's manual or the manufacturer.
You can also check out the following web sites:
Modem
Disconnections
Call
waiting
A
common cause of a modem disconnection is call-waiting. If your
connection freezes up for a period of time, or you are disconnected
suddenly and the phone starts ringing, you probably did not turn off
your call-waiting. It is possible to deactivate call-waiting for
outgoing phone calls by dialing *70 or 1170, before dialing a number.
Line
noise
Line
noise is perhaps the most difficult of these problems to solve. When
you place a telephone call, the data, be it your email or your voice,
is transferred through different exchanges within the phone company
and eventually routed to us. Anywhere along the way something can
cause line noise, which is characterized by the sound of static, or
intermittent popping, which you might hear when your modem is dialing
in. There is a great page on the web that can help you figure out if
you have noisy lines or not. Go here
to learn more. If you suspect that line noise is a problem, you
should contact your phone company to test your lines.
Configuration
problems
The
configuration of your communications software may also cause
problems with your connection. A few of the things that you can
double-check are that you have hardware handshaking active, or set to
CTS/RTS. This ensures that communication between your computer and
your modem are properly regulated. You should also avoid selecting
any option that says "Connect at this speed only" which may
force certain modems to disconnect under noisy conditions rather than
change to a slower speed.
Communications
overflow
If
you are using an older computer, it may be possible that your
computer is incapable of handling higher speed connections. You might
try lowering your baud rate. It
may be possible to upgrade your computer's UART chip to handle
the speeds of modern high-speed modems.
Buffer
size
By
reducing your transfer buffer size under Windows© 95, you can
improve communications reliability. To decrease this buffer size, go
to the "Modems" control panel. Select your modem and go to
Properties. On the Connection page is a button for Port Settings.
Select this and slide the sliders in the pop-up window over to the
left one notch.
IP
Packet Size/MaxMTU
Certain
Windows default settings including MaxMTU (Maximum Transmission
Unit), RWIN (TCP Rcv WINdow) and TTL (Time To Live) may not be set
optimally. Basically, these are settings which can help prevent
fragmentation in data transfer using the TCP/IP protocols used on the
Internet, and greatly increase modem throughput. To optimize IP
Packet size in Windows© 98, open Control Panel, then Network.
Highlight Dialup Adapter and press Properties. In Properties, go to
the Advanced tab. Select IP Packet Size under Property and Small
under Value. Ok out and restart the computer when finished. For
Windows© 95 & 98 users, there are programs to automate this
process-many of which are free. See our Links
page for our favorite Shareware/Freeware links.
Modems
Some
modems have design problems which can sometimes drop connections. If
you have a modem that you suspect might have some internal trouble,
you can contact the manufacturer directly. Some problems we've found include;
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