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Build Your Own PC: Dial-up Modems - Page 2

Last updated on 25 August 2005

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This article consists of six pages. You can access the other five pages by clicking the relevant hyperlink below.

Troubleshooting a dial-up modem

Not installing or configuring a modem properly is the cause of most problem. There are many sites that show you in illustrated detail how to configure a modem for the best results.

For example, troubleshooting advice on a wide range of modems is given at - http://808hi.com/56k/trouble.htm#trouble

However, it can be a problem if you use Windows XP that you won't be able to make the modem hang up. If this is the case, the information in Modem Issues: Auto-Connect/Disconnect & Dialup for Windows XP at http://www.kellys-korner-xp.com/xp_modem.htm will probably provide the information you need to sort the problem out.

If there is no such known issue with a modem and a version of Windows, which can usually be discovered by searching the MS Knowledge Base, the next step you should always take if you have trouble with a modem is to search the Internet for links to its make and model from a library, Internet Cafe, or by using a friend's connection, etc.

You'll quickly discover if there's a bug plaguing it. For instance, Aztech V.92 modems were disconnecting often after a message saying: "You have just ignored an incoming call," came up. You can make use of the Google search box at the top of this page (with its Web radio button enabled) to enter a search term such as aztech + V.92, which should bring up links that would tell you of a bug with these modems that can be rectified by downloading the latest driver file, etc.

If there are no such bugs, the next step to take is to troubleshoot the problem.

You can download useful modem utilities (paid-for or free). Click here! to view the links to diagnostic programs, and click here! to visit many modem-related links on the second of the four Links pages on this site.

CheckIt NetOptimizer from the TouchStone Software Corporation is a reasonably priced utility that can optimise the hidden dial-up networking settings, such as TTL (Time to Live), MTU (Maximum Transmission Unit) size, test a modem, run a troubleshooter, and monitor of the actual connection speed. This utility is often given away free on the cover disks of computer magazines.

For more information about it, visit http://www.touchstonesoftware.com.

You should read and understand all of the information it provides in its Help files before changing any settings.

The CheckIt PC diagnostics application from the same company also provides modem tests.

Don't forget that viruses, worms, spyware, adware, and Trojan programs can often be responsible for destroying a connection that used to work perfectly. For computer security information on this site visit the Security pages on this site.

A typical modem troubleshooting problem

Problem

This is by far the most common problem Windows 95/98/Me/XP and Internet Explorer users experience with regard to loss of Internet connectivity.

You have a Windows 95/98/Me/XP system, and when you dial up your ISP (Internet Service Provider), the PC's browser makes a connection via the modem, but no web pages are displayed, or e-mail cannot be downloaded or uploaded, and you have to disconnect by right-clicking the Dial-Up Networking icon in the System Tray/Notification Area.

Possible solutions

The first action to take is to make sure that you only have Internet Service Provider (ISP) software installed that you use. If you have installed the software of many ISPs in order to try them out, you must remove the ones you don't use regularly, because each ISP makes changes to the system, many of which can screw it up for other ISPs. Often it is difficult to remove an ISP's software, because no uninstall utility is provided, either in Add/Remove Programs or in Start => Programs/All Programs, so the best advice is not to install free ISPs just to try them out unless you can find out how to remove them first.

The second action you should take is to check the settings of any firewall (ZoneAlarm, Norton's Firewall, etc.) that is installed on the system and set to load at system start-up. Often the firewall can somehow have been set to prevent Internet access by the browser (Internet Explorer, Opera, Mozilla, etc.), or the e-mail program (Outlook Express, Eudora, etc.) If the settings are correct, disable the firewall and then try accessing the Internet, or try using the e-mail program, because, for reasons unknown a firewall can prevent access even if the settings are correct. I have even accessed a suspect website listed in a computer newsgroup that was somehow able to set ZoneAlarm to prevent Internet Explorer from accessing the Internet.

If the firewall is not to blame, you should check to make sure that all of your modem's settings and Dial-Up Networking (DUN) settings - as discussed earlier in the article - are correct.

By left-clicking on the DUN icon on the Windows Desktop, and clicking on the entry for your ISP, and then clicking the Dial Properties button, you can check to see if the correct dialling property is enabled. Most modern telephones use Tone instead of Pulse dialling.

If an ordinary left-click on the ISP entry brings up a message saying something like, "Unable to use the listed modem to make a connection", the wrong modem has been set as the default modem. Often if you have installed more than one modem during the computer's life, an uninstalled modem will still be listed in the drop-down menu (accessed by right-clicking on the ISP's DUN entry), and may have somehow become the one chosen to use DUN. If so, just use the drop-down menu to select the current modem that is listed in the Device Manager.

By using the right mouse button to click on the ISP entry and then clicking Properties, you can check if the correct telephone number to your ISP is listed.

If the use of a proxy server is enabled under Connections => Settings section of Internet Properties, disable it by removing the tick in the check box next to Use a proxy server for this connection.

It is unlikely that running the Windows Modem Troubleshooter in a Windows 95/98/Me system will solve this problem, because it is too basic, but if you have not tried it, you might as well do so just to get an idea of its abilities. Look it up under Start => Help. But Help and Support provided by Windows XP is far superior, so might be of assistance.

The ISP's server could be responsible for the problem, but that is unlikely if you fail to make a successful connection over a period of days, because ISPs usually rectify problems at their end fairly quickly.

If you have two ISPs installed, try using the other one if one of them gives problems. If one works and the other doesn't, you know where the problem lies immediately.

Otherwise, the cause of a connection problem is most likely to be corrupt Dial-Up Networking files on your system that were messed up or corrupted by the installation of one or more conflicting programs, such as firewalls or antivirus programs, or by a virus. So check for viruses with an updated antivirus program, and then remove or disable it and any firewall program(s) you have installed.

If none of the above is the cause of the problem try this next. - Windows 95 does not have the following utility, but in Windows 98 and Windows Me, you should run the System File Checker (SFC) under the Start => Programs => Accessories => System Tools => System information menu.

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The System File Checker (SFC) is still present in Windows XP and Windows 2000, but it is run from the Command Prompt instead of via Accessories => System Tools or by entering sfc in the Start => Run box as it is in Windows 98/Me.

To find out what the commands and switches are, open the Command Prompt by entering cmd in the Start => Run box, and then enter sfc /? to bring up a list of them.

Take care when using this utility, because if you allow a file that Windows updates with current data to be replaced with an empty file from the Windows CD, the system could experience problems such as not being able to boot.

You should have a certified Windows XP CD - not a System Recovery CD of the kind that comes with many brand-name computers instead of a Windows CD - because the SFC utility makes use of it.

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You should use the SFC to check the system's files, and you should use the utility to replace any corrupt files. Especially if the wsock32.dll (winsock) file is named. This is an essential part of Dial-Up Networking software that makes dial-up modem calls. There may be more than one version installed, but the correct one is in the Windows\System folder and have a file size of 65KB for Windows 95 and 40KB for Windows 98 and its date should match the date given for the other files in the folder.

If that does not work, or you could not attempt it because your version of Windows does not have the System File Checker (Windows 95), you should try removing Dial-Up Networking, and then reinstalling it.

If you have installed an updated version of DUN, it should be listed in the Add/Remove Programs => Install/Uninstall tab, which is accessed via the Control Panel (Start => Settings => Control Panel). If it is listed there, you can highlight it and click the Add/Remove button to uninstall it.

If DUN is not listed under the Install/Uninstall tab, click the middle tab called Windows Setup. Click on the Communications heading to highlight it, and click the Details button. Its check box will have a tick in it. To remove DUN, just remove the tick, and click the OK button.

Windows might ask you to insert the Windows CD in the CD-ROM drive. You can avoid this by creating a folder called Win98, and copying the whole Windows CD into it...

If you don't know how to create a folder using Windows Explorer, consult the Start => Help files. Enter the word folder in the search box, and when the options are presented scroll down to and click creating...

Whenever the system asks you to load the CD, use the Browse option to navigate to the Win98 folder, which could be placed on a different hard disk drive, or a separate partition on the boot drive, or just in a folder of its own on the C: drive.

Reboot so that the removal of DUN is complete.

To reinstall DUN, all you have to do is reverse the process by clicking inside the empty check box beside Dial-Up Networking. Windows installs any option with a tick in its check box and removes any option with the tick removed.

You will have to reboot to complete DUN's reinstallation.

Alternatively, you can download and install the latest version of Dial-Up Networking - version 1.4 for Windows 95/98/Me systems - from Microsoft.

In Windows XP, look under Start => Help & Support => Index for information on removing DUN.

If doing that has not solved the problem, you will have to conduct a step-by-step search for the source of the problem, as follows...

Connect to the Internet.

Click the Start => Run. Enter winipcfg, which stands for Windows Internet Protocol Configuration. The window that presents itself should show the four settings for the PPP Adapter,which is another name for the dial-up networking connection. - PPP stands for the point-to-point protocol.

Click on the More Info button. Look to see if an IP Address is given. (IP stands for Internet Protocol.) If the setting is shown as zero, or has an auto-configuration IP address in the range 169.254.xxx.xxx, then DUN did not make a successful connection to the network.

If you are connected, the IP Address that shows is the dynamic one assigned by your ISP, which will be reassigned to someone else when you log off. There will also be addresses shown for the DHCP Server and the Default Gateway. - DHCP stands for Dynamic Host Configuration Protocol.

The DHCP server is the computer on your ISP's network that responds to requests for an IP Address. You have to have an IP address so that your ISP's modem can establish a connection with your computer via DUN. The DHCP server also tells the connecting computer which gateway to use and usually also which DNS server to use. - DNS stands for Dynamic Name System.

The DNS server is the computer that translates the web domain name into its IP address. For example, the UK domain name for the Internet service provider (ISP) Netscape Online was http://www.netscapeonline.co.uk, and its IP address was 194.200.20.15 (on 27 June 2002).

To bypass the DNS server, you would have to enter the IP address instead of the domain name for each website in order to connect to it.

Most ISP's send their DNS server's address when they allocate your system a dynamic IP address, but some ISPs require that you enter it in the IP Configuration window (Start => Run => enter winipcfg).

Of course, any ISP that requires you to configure DUN will tell you how to do it when you install that ISP's software, otherwise you would never be able to establish a connection to it.

Confusingly, Microsoft also allows you to set your ISP's DNS server address under Network in the Control Panel by clicking the Properties button with TCP/IP highlighted. But you should not do this if you have more than one ISP, or DUN connection, because this setting will override all of the others. That is why you enter winipcfg in the Run dialogue box after you have dialled the ISP you want to connect to. You want to see the settings for that connection, not any other.

Solving this problem may require finding out if you have the correct DNS server for the ISP you want to connect to, and if it can be reached. This is done by by using the ping command in DOS mode. When you enter the ping command, it sends a test message to the IP address in the command, and then shows if a response was received.

While connected to your ISP, open a DOS window by entering the word command in the Start => Run box in Windows 95/98/Me. Under Windows NT/2000/XP, click Start => Run and enter cmd.

When a DOS window opens, type in ping followed by a domain name for your ISP and press the Enter key. You could also enter any other domain name such as http://www.netscapeonline.co.uk, because you are testing if the DNS server is able to translate a domain name into an IP address.

You can find out what the IP address is for any website by using the command ping followed by its domain name in at a DOS prompt (usually C:\>) while online. For example, to obtain the IP address for eBay.com, enter the command - ping http://www.ebay.com/.

You should get a reply giving the number of packets received and the time taken.

If that did not happen, enter the IP address that corresponds to the domain name, which for the Netscape Online example is ping 194.200.20.15.

If you get a reply using the IP address - in this case 194.200.20.15 - you know that the TCP/IP system is working, and that the DNS system is not working.

If you did not get a reply, then the chances are that no connection was made, or the ISP's network is at fault.

Next, you should try sending the ping command with the other IP addresses listed in winipcfg - or IP Properties.

If you don't even get a response using the gateway that has been assigned to your system, as a last resort try entering the command:

ping 127.0.0.0

This address is called the localhost. It's your computer's local host address. If it cannot ping itself then the TCP/IP networking on your computer has been irrecoverably corrupted and you will have to remove and reinstall it.

You should click Start => Settings => Control Panel => Network, and remove all of the TCP/IP entries you see under the Configuration tab - Client for Microsoft Windows - Dial-Up Adapter, TCP/IP, and any others. Just click to highlight each entry and click the Remove button. Reboot, and then reinstall Dial-Up Networking by using the Add/Remove Programs' Windows Setup tab - as described earlier.

If that doesn't work, you will probably have to reinstall Windows over itself, choosing the custom installation in order to install DUN. You can reinstall Windows over itself and your data files will be preserved, but you will have to reinstall all of the applications that have placed entries in the Registry, because reinstalling Windows destroys the old Registry and creates a fresh one.

If you have back-ups of all of your data files - My Documents, Internet Explorer Favorites, the Windows\Application Data folder where all of your e-mail and newsgroup information is stored, etc., you can start the system in DOS mode (by pressing the F8 or Ctrl key at start-up before Windows starts to load), and reformat the drive by entering the reformat c: /s command at the C:\> prompt. Note that this method destroys all of the data on the boot drive, so you must have CDs for Windows and your applications, or have the system properly backed-up so that it can be restored.

That is why it is a good idea to purchase a CD-R or CD-RW drive in order to create a restorable back-up of your whole system on a CD-R disk. You can do this by installing Windows on the C:\> drive and your data files and programs in their own partitions, which Windows will give drive letters, such as D:\> and E:\> - with the CD drive as F:\>. - On a newly formatted hard disk drive, you can use the Windows FDISK program to create as many partitions as you like, but you require a program such as Partition Magic in order to create partitions on the fly. Partition Magic can delete, re-size, and create partitions without destroying any data, but using FDISK to create or remove partitions will destroy all the data on the drive.

FDISK is simple to use. You create a Primary partition that can be the entire drive, or add an Extended partition to it in which you can create as many logical drives of any sizes as you want as long as they don't exceed the total disk space. - Click here! to go directly to some relevant links on FDISK on this site. Entering fdisk in the Google search box at the top of this page will will present you plenty of other useful links.

See the Disk Drive page on this site for more information on HDD, CD, and DVD drives.

But before you take any action, Windows 95/98/Me users read the following Microsoft Knowledge Base articles that cover this sort of problem - 181599, 151237, and 169790. Windows XP users should look at article 314067, and Windows 2000 users should look at 102908.

See the Diagnostics page on this site for information on many Knowledge Base articles and how to access them.

A good tip

If you have to switch between modem and telephone manually by connecting the modem's or telephone's jack to the telephone socket, and you cannot go online with the modem because it cannot detect a dialling tone, remove the cover from the telephone socket and make sure that all of the connection pins are aligned correctly. It is possible that the constant change of jacks forced one or more of the internal pins out of alignment so that it might even come into contact with another pin. This happened to me once. The telephone worked properly, but the modem kept coming up with a message that no dialling tone could be detected. The pin that provides the dialling tone was shorting another pin. I thought that I has been infected with a virus when all sorts of strange symptoms plagued my system into the bargain. I did a complete reinstallation of Windows that had no effect before it occurred to me to check the telephone socket for irregularities. The fact that the telephone was working perfectly made me dismiss the socket as a possible source of the problem.

Connection speeds measured in kilobits and megabits, kilobytes and megabytes

Note that dial-up and broadband connection speeds are usually given in kilobits and megabits per second (Kbit/s and Mbit/s. A Mbit is 1024 Kbits). There are 8 bits in a byte, so to get the speed in kilobytes (KB) and megabytes (MB) respectively, the figure has to be divided by 8. A 1Mbit/s connection speed is therefore really only 128 kilobytes per second (128KB/s), which is pretty fast considering that the usual actual connection speed of a 56Kbit/s dial-up modem is only about 4.6 kilobytes per second (4.6KB/s). Click here! to go to a more detailed calculation on this page. Use your browser's Back button to return to this point on the page.

"Many cable companies tout cable modems as fast as 100 times faster than dial-up Internet connections - that, however, is a slight exaggeration. Theoretically it can be done, but realistically, for a number of technological reasons, it rarely occurs in practice. A more accurate figure would be about 20 times faster than a 56K dial-up connection" - http://www.cable-modem.net

Dial-up modem sites

Rockwell, the modem chip maker, is now called Conexant - http://www.conexant.com/

US Robotics (USR) - http://www.usr.com/

The Modem Site - http://modemsite.com/

Click here! to go directly to many relevant and useful links on the second of the four Links pages on this site.

There is a Google search box at the top of this page that you can use to search the web for further information.

Broadband cable and ADSL modem information and sites

How to optimise your broadband connection

This site offers some excellent free tests and tools to help you get the most out of your DSL, Cable or Satellite Internet connection. - http://www.dslreports.com/tweaks

Cable

Cable access makes use of a different kind of modem to the type used for a dial-up telephone connection. The cable company supplies the modem unless it is built into a digital television set-top box. A standard Ethernet network interface card (NIC) is required to connect the external cable modem to the computer.

The UK's has two main cable companies - NTL and Telewest owner of Blueyonder. Although they have some coverage in common, they mostly cover different areas of the UK. UK cable coverage is still patchy, with most of the country uncovered.

To increase your broadband cable modem speed, visit http://www.speedguide.net. The site has some excellent registry and .inf files to download to improve cable access.

Cable sites

Robin Walker's Cable Modem Pages - http://homepage.ntlworld.com/robin.d.h.walker/

How Cable Modems Work - http://computer.howstuffworks.com/cable-modem.htm

Cable-Modem.net - http://www.cable-modem.net/

ADSL

An ADSL connection requires an ADSL modem, and a router to connect it to the telephone line. British Telecom (BT), the only provider of this service in the UK charges for the installation of the service, and the modem and router. You can purchase an ADSL connection from an ISP, such as Wanadoo, but it will be obtaining it from BT on your behalf. The ISP will purchase the service from BT at a discount and then sell it to you. You will then be connecting to the ISP's servers instead of BT's.

Telephone lines that have been specially adapted to provide ADSL via telephone exchanges. BT has about 60% of the country's exchanges converted, and aims to have the the others converted soon.

To check in the UK if you have an ADSL telephone exchange, click http://www.bt.com/ and search for information about ADSL.

In the USA, look here - http://www.nwfusion.com/research/dsl.html

ADSL sites

How DSL Works - http://computer.howstuffworks.com/dsl.htm

How VDSL Works - http://www.howstuffworks.com/vdsl.htm

ADSL Guide - For advice on (A)DSL connections to the Internet. -

http://www.adslguide.org.uk

DSL Resource Page - http://www.nwfusion.com/research/dsl.htm

You can use the Google search box at the top of this page to find out more information on any of these topics.

Megabits

Note that a megabit is 1048576 bits (1024 X 1024). To convert megabits to bytes, divide the megabits by 8, because there are 8 bits to a byte. Divide the bytes by 1024 to derive the kilobytes per second, and divide the kilobytes by 1024 to derive the megabytes per second. These communications companies clearly use megabits per second because it looks more impressive than in kilobytes per second, etc.

E.g., 38 megabits per second is 38 X 1048576 bits = 39845888 bits, because there are 1048576 bits in a megabit.

This is 39845888 divided by 8 = 4980736 bytes.

Or 4980736 divided by 1024 = 4864 kilobytes.

Or 4864 divided by 1024 = 4.75 megabytes per second.

Impressive, but it doesn't sound as good as 38 megabits per second, does it?

Standard 56K modems measure their speed in kilobits per second (Kbit/s). One kilobit is 1024 bits per second, so a 56K modem working at 53 kilobits per second is really only working at 1024 X 53 = 54272 bits per second, which is 54272 divided by 8, or 6784 bytes per second, which is only 6784 divided by 1024, or only 6.625 kilobytes per second. Indeed, you will be lucky if a 56K V.90 or V.92 modem downloads at more than 4.6KB per second. Moreover the uploading speed of such a modem is the same as a 33.6K modem. - A 33.6K modem's maximum speed is only around 3.3KB per second. A V.92 modem's uploading speed is about 1KB per second faster.

Troubleshooting and other websites

If you want to troubleshoot, tweak, or optimise your modem , visit these sites.

Troubleshoot modem problems - http://modemsite.com/56k/trouble.asp

The 56K Modem Troubleshooting Guide - http://www.56k.com/trouble/connect.shtml

Tweaking and optimisation

http://www.dslreports.com

http://www.speedguide.net/

http://www.tweak3d.net/tweak/modem/

http://www.modemsite.com/56k/speedup.asp

http://www.google.com/search?hl=en&lr=&q=modem+tweak+rwin+mtu

OTHER SITES

How [Dial-Up] Modems Work - http://computer.howstuffworks.com/modem.htm

Click here! to go directly to many other modem-related sites on the second of the four Links pages on this site, several of which provide driver information/downloads, and modem-identification information.

Google searches

If my descriptions are not clear enough for you, you'll be able to find many sites offering illustrated information on how to install computer components by entering a phrase such as "install a xxxx" (where xxxx stands for the device, such as RAM, hard disk drive, etc.) in the Google search box at the top of this page (with its Web radio button enabled).

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