Why do my online connections ‘pause’ or stop?
Sometimes when you are online, your modem may stop sending and receiving data for a minute or so (or longer), with the result that you cannot access Web sites, check email etc. Then, just as suddenly, it will resume where it left off.

There are several potential causes for this scenario, which can make troubleshooting the problem quite difficult. Below is a list of factors for you to investigate.

Before you invest too much time in the problem, however, the most likely solution to the problem is to disconnect from the Internet, reboot your computer and then reconnect. In most cases, this will solve the problem.

Telephone problems
Modem error recovery: When most modems experience errors while sending or receiving data, they will automatically retransmit the corrupted data. Usually this will take a few seconds at most. But when the modem connection itself is poor (due, say, to excessive line noise), there will be more frequent data corruption, which will require more frequent retransmissions. The retransmissions themselves may need to be repeated due to the poor connection quality. All of this will slow down your modem, giving it the appearance of pausing.

Modem errors are generally intermittent. However, you should have your telephone line tested for line noise.

Modem retraining: When a modem encounters line noise during a connection, it will automatically ‘retrain’ itself (that is, test the line to determine the highest speed at which it can send and receive data without error). While a modem is retraining, no data can be sent or received. Normally retraining takes only a few seconds, but if the line noise becomes excessive, the retraining period can continue for longer periods (up to almost a minute).

Network problems
Lost data: The Internet is designed in such a way that it can continue working even under extreme circumstances (such as when several host computers are offline). This is achieved by using network protocols, such as TCP/IP, that have ‘error detection’ capabilities.

All Internet data communications involve a two-way dialogue between the sending and receiving computer. For instance, when you connect to a Web site, the Web site computer will send data to your PC. When it is received, your PC will send a reply to the Web site confirming that it was received. The Web site will then send some more data and so on.

When data goes missing during a transmission of data (say, because the network is overloaded or congested), your computer won’t acknowledge receipt, which lets the Web site know that it must retransmit the data. The resent data may itself go missing but both computers will retransmit the data until it gets through. This may result in a decrease in data transmission speed, or even a pause, until the problem is overcome and the data is successfully sent and acknowledged.

Server overload: From time to time, some Internet hosts (such as Web sites) become overloaded. Basically, there are more people trying to access the host than it can handle. You may experience slowdowns and pauses while the server is busy attending to other users. Such overloads generally resolve themselves, usually within minutes. If you frequently encounter this problem with specific Web sites, you should try accessing them during non-peak times.

Network congestion: Excessive delay may occasionally be encountered as a result of network congestion. As mentioned earlier, the Internet is designed to be fault-resistant. If one section of the Internet is ‘out of order’ due to, say, a fibre network cable being cut, then the network traffic will be dynamically re-routed around the problem area so that data will still flow. This may, however, put pressure on the sections of the network that are taking on the extra traffic, which may cause a decrease in speed over the network. Again, this problem is generally transient, and will resolve itself.

Hardware problems
Flow control: Modems handle lots of individual bits of incoming and outgoing data in any given second. To handle this flow of data, it uses ‘flow control’ technology. Flow control can be handled by your modem’s software (software flow control) or by the modem itself (hardware flow control).

It is recommended that you use hardware flow control. To check that your modem uses the hardware flow control setting, follow these steps:

1. Double-click My Computer.
2. Double-click Control Panel.
3. Double-click Modems.
4. Highlight your modem (if necessary) and click on the Properties button to display the Properties dialog box.
5. Click on the Connection tab.
6. Click on the Advanced button.
7. Toggle the Use flow control option.
8. Click the Hardware option.
9. Click OK.

Serial port: The job of allowing your computer to communicate with your modem falls to your PC’s serial port.

If your PC has an old serial port or if it is experiencing faults, this may cause modem problems, including sporadic pauses. The easiest way to tell whether your serial card is too old or faulty is to have your PC inspected by a technician.

Software configuration problems
Dial-up Network settings: If your Dial-up Network settings are incorrectly configured or the settings have become corrupted, this may interfere with normal data transmission.

Multi-tasking
Modern computers can handle many tasks at once. But if your computer becomes busy doing something else while you are online, it may result in temporary pauses in the modem’s activities as your PC puts some of the tasks ‘on hold’ until it completes the others.

This can be a significant problem for ‘software modems’ or ‘Win modems’ (that is, modems that rely heavily on a PC’s CPU for much of its activities).

To avoid this problem, close any unnecessary programs while you are connected to the Internet.