Disconnection Tutorial


Unfortunately there is no simple way to resolve modem disconnects. There are many factors that influence disconnects, but the bottom line is that disconnects occur when the modem receives errors in the incoming data. The trick is trying to determine what is causing--or at least contributing to--these errors.

The most common culprit is the physical phone line itself. It could be between the phone jack and your modem, or in your internal wiring, or external to your home entirely. Here are some tests to perform--in order--to try to narrow down the problem.

Make sure your mail program is not disconnecting you. Outlook Express has a setting to automatically hang up the dialup connection when it's done sending/receiving. If you get disconnected immediately upon checking your mail, this is probably your problem. You don't actually have to tell Outlook Express to do the send/receive, as it will automatically do it on its own every 15-30 minutes, depending on your settings. If Outlook Express is open, but you're browsing the web or working in another program, and it does a send/receive, it will disconnect the connection. To check/disable this setting:

Make sure your computer is not set to disconnect you if idle for a certain amount of time. ACD.net does not disconnect any customers for being idle for any amount of time. To disable this:

Do you have call waiting on this line? Some modems cannot handle the *beep* of an incoming call. To get around this you would want to disable call waiting when you get on the internet. To do this in Windows 98 and Me, you can follow the instructions in Microsoft Knowledge Base article 275578, located at http://support.microsoft.com/?kbid=275578.

Update your modem drivers. This error can be caused by problems with the modem drivers, which are used by Windows to communicate with your modem. Contact your hardware vendor to obtain the most recent drivers for your modem.

Try to eliminate noise/interference. The problem could be caused by interference or noise on the line corrupting the username/password between your computer and our authentication server. Many times line noise is caused by something on the line external to the home, but due to the nature of telephone wiring and its susceptibility to interference there are several things you can do to ensure you are not contributing to line noise inside the home, such as:

Do you get disconnected every time you connect? Customers who get disconnected all the time are the easiest to troubleshoot, as after making any changes it's obvious if it made a difference. If none of the above steps isolate or resolve your problem, the best test you can do is try to connect from another location. You can start by just trying a different phone jack in the house, or if your computer is on its own line try to use your main line. If nothing you do inside the house does the trick, it's time to take your computer elsewhere. A friend's house (whom you know is not having disconnects) or a computer repair shop for example. The following is an anecdote from Joe Grover, Internet Support Manager:

"I personally had great difficulties with disconnects at one time, however after doing everything I could with my PC (updated my modem drivers, even tried a different modem entirely) and home wiring (tried every jack in the house, as well as the main phone line jacks) I took my computer to a friend's house. Not only did I connect at twice the normal speed (just over 49k instead of only 24k), I stayed connected all day on his data line. As soon as I took my computer back home I was disconnected within 5 minutes of dialing in. The following week I took my computer to work and dialed in from there. I connected at 52k and stayed connected throughout the day. Again after taking my computer home I couldn't stay connected for more than 5-10 minutes. This proved that the same computer with the same modem dialing into the same number had no problems whatsoever when dialing from a different location. The problem was clearly with my own phone line.
I contacted SBC and informed them of the problem. I asked if there was anything they could do, and clearly stated that I knew they weren't responsible for data communications on their phone lines (the line worked fine as a voice line). I told them if they couldn't help me I would totally understand, but just please let me know up front, as if I can't get the issue resolved I wouldn't need that line any longer. Surprisingly (or maybe not so surprisingly as they would lose business otherwise) they were willing to help.
Over the next few weeks they tried various things to resolve the problem. They moved my phone service to a different phone card at the local central office. They cleaned up the crossbox at the end of the road. Nothing was doing any good. Finally they scheduled a technician to come out and test at my phone network interface on the house. The technician arrived and upon looking at my wiring in the phone box he immediately told me he's pretty sure the problem was the cable going from my house to the road. When asked why he told me he could tell the wire was old, as it only had two pairs of wires in it, and he said SBC hadn't used two-pair cable in at least 20 years. My house was built in 1967, and he said that's probably when that cable was buried and it hasn't been touched since. He told me that over the years any number of problems could occur as the ground shifted, rocks and earth would rub against the cable (it isn't buried in any conduit, it's just laying in the ground).
He then performed what's called a "stress test" on the line. This test measures noise interference and resistance on the line. The tech informed me that SBC policy (and most other providers' policy as well) is that anything up to 30dB of stress is considered acceptable. Ideal circuits stress under 20dB. Anything over 30dB is considered excessive and steps should be taken to bring it under control.
The stress test indicated I had just over 45dB of stress on the line. The technician told me that while this would likely never cause a problem if I were only using the line for voice (if I started hearing static on the line I'd be getting closer to the 60dB range), a modem is trying to use all available bandwidth and signal on a pair, so it will definitely have problems at that stress level.
The technician had a spool of five-pair cable on his truck, so he ran a new cable across the ground between my interface box and the post out by the road. He hooked up the cable and asked me to connect to the internet. I did so and connected at 33.6. We stayed on the front porch for almost an hour as I grilled him for more information about problems such as this, and during that time I never got disconnected.
Once I was satisfied he placed an order for SBC to come out and bury a new cable for me (the cable running across my yard was only temporary--he left a bunch of slack in it so I could move it around if I mowed the lawn). SBC came out a week later and buried the new cable, then came back a few days later to switch me from the temporary cable to the new cable. I stayed at that location for 3 more years and never got disconnected once.
I would like to state that *all* steps should be taken on the customer end before getting the phone company involved (unless of course there are obvious voice line issues as well), as had SBC come out and found no problems, I likely would have been billed for the visit. I felt confident that I'd done everything in my power to ensure the problem was not on my end before calling SBC (the technician agreed), so I had no doubt where the problem was. Remember: Don't call SBC until you've at least checked your connectivity from another location!"

Does it matter what time of day you're having the problem? If the answer is yes, then there is very little you can do. When customers are experiencing different performance at specific times of the day the issue is usually caused by something called "pair gain". For a definition of pair gain, you can visit the following links:

http://www.keypoint.com.au/knowledge.html?strid=1137
http://en.wikipedia.org/wiki/Pair_gain
http://www.easynet.net.au/support/?article=10

Basically, since there are a finite number of copper pairs available between your local phone switching office and your home, the phone company will at times put more than one customer on a particular pair of wires when they begin to run low. They do this by taking, say, 8-10 customer lines at the central office and connecting them to a pair gain multiplexer. One pair of copper (essentially one phone line) comes out of this multiplexer and goes to a particular area--say an apartment complex, a subdivision, or just a neighborhood that may have been running low on phone lines. At that end is another multiplexer that breaks the signals back out into the 8-10 pairs of copper, each of which going to the customer site.

Since voice traffic only uses 4-6 kilobytes per second, this typically doesn't cause problems for voice communication--8-10 customers going across that single pair of copper between the multiplexers likely won't notice a problem unless something is wrong with wiring somewhere.

However if you put a bunch of customers on one pair and one or more of them uses the line for modem traffic--which tries to use all available bandwidth--you will run into problems.  In the evening more of the people on your copper pair are probably using the line (people home from work for example) than there are in the morning, or maybe vice-versa--it depends on who's on your line and what they're doing.

If you are having disconnection problems at certain times of day, the best test would be to try to connect from another location at a time that you know you'd have problems at home. Ask any computer repair shop technician and they will tell you that customers bring in computers all the time saying they're having a problem getting connected/staying connected, but it works fine in the shop. This is always indicative of a customer phone line or wiring issue.