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About 56k Modems

Disconnections from the Internet and Other 56k Issues

The issues surrounding frequent disconnections from the Internet when using a 56k modem are not unusual. 56KB modems are discussed in great detail on all the news groups and are a general discussion of most ISPs. The facts are that 56KB modems are generally less reliable than its older V.34 counterpart. In order for you or anyone with any ISP to establish a reliable 56k connection is dependent on many items. We have seen a general upgrade in most customers speeds and connection reliability as V.90 firmware has evolved. We continue to upgrade our V.90 code as the industry and standards evolve.

The issues with reliability are usually one or more of the following issues:

1. Modem and Modem Firmware

2. Phone line

3. Phone line interference or padding devices

1. Most modems (even brand new) come with a version of V.90 code which was developed based on certain standards when initial engineering of the modem began. V.90 has been changed substantially. Most modem manufactures offer frequent changes to their firmware as standards change and bugs are identified. We suggest you update your modem firmware to have the most stable and reliable connections possible.

There are two main types of modems on the market. Hardware and software based modems. Software based modems are by far the most frequently sold modems. They claim many great things, such as, you will never have to upgrade them, instead just download the latest updates. These software modems use a modem card that has less chips on it and therefore costs less to make and sell. The cost benefits are far outweighed by the reliability and speed issues with these modems. The actual communications, error correction and compression, plus V.8-V.90 codes all happen within your CPU. Many modems can tax your CPU to a much greater extent than a hardware modem (some software modems or WinModem as 3COM calls them, are better than others). One fact about software modems is that, if your system is not working perfectly or you are running heavy applications, such as graphical games, your connections are going to be much less reliable.

2. Phones line are completely out of the control of ACS Online. They are a very frequent cause of disconnections. The main problem is that phone line quality is changing all the time. Your modem should respond to the changes and slow down and or ask the other modem to resend information not properly received. This is the function of error correction. Many 56Kb modems will disconnect as phone line problems get worse, instead of slowing down. A firmware update for your modem may help. 56KB technology (V.90, kflex, X2) all rely on the same phone line elements. They require no more than one analog to digital conversion. These A/D conversions happen between your line and US West's main switch. Unfortunately as new subdivision and new phone services are added to the area, US West can and does change the routes to and from certain houses. Basically they change the switch or switches you go through. If you have more than one A/D conversion you will either see slow speeds or disconnects. You do not generally have any control over this part of the connection. Most phone companies not very receptive to making changes to benefit data communications.

3. Padding devices are products applied to a line that cause lines to behave differently. A common padding device is used by US West to clean phone line buzzes. It is placed on your subdivisions phone connection or house. There are several other padding devices that they use. One padding device that you use is a caller Id box. Caller Id takes two parts, first US West needs to set up the service for you on your line and second you attach the device to your line. Caller ID is a common problem for 56KB modems. The technical reason is as follows. Telcos use either RBS (Robbed bit signaling) or SS7 (Signal System 7) to achieve caller id. In either case the basics are to take one bit per 6 8bit samples and transmit caller id info. Your 56KB modem assumes that all bits are for its use and many will disconnect when RBS or SS7 are present on the line. The caller ID box itself can be the problem. They are in fact a padding device that take power off the line, plus they have a signal on the line looking for RBS/SS7 information. We have had several cases where users unplugged there caller id and stopped getting disconnected, although in a perfect world you wouldn't have the signaling on the line either.

The more phones or phone line devices (answering machines) you have on the line, the less power is available for communications as well. Again in a perfect world you would reduce your number of devices down to your computer.

In troubleshooting disconnection problems, our suggestion would be to upgrade your modems firmware to the latest code available. Unplug all of your phone line devices including caller id, answering machines and phones, then try your connections again. See if that helps. If not, my suggestion would be to put in your extra settings the AT commands necessary to achieve a v.34 connection. This will generally fix any issues.

If this doesn't fix the problem either, we would suggest a different modem.

Our connections to US West are via T1-Pri lines and are monitored consistently for problems. US West has certainly had some issues over the years; however they are not very often or for very long. Our system is currently at less than one half capacity and our bandwidth is presently fairly low with a lot of growth room. We have updated our V.90 code regularly as reliable updates are available. Any speed issues as far as throughput are concerned are very difficult to monitor.  Unfortunately using any TCP level monitoring to see throughput will give you false readings. If you want to get a pretty good metric of speed, download a 1mb file from the same source 10 times a 10 different time periods, then do it again from another source. Divide and average and this will be a pretty close metric of speed. If you were to do this with a different ISP or at a different time period with us, you could figure out some issue with speed. The reporting happening on your IE or Netscape browser is based on TCP feed back and then a mathematical guess by the browser, which is why the finish times are never correct.

 If you have any questions please call or office or direct them by email to: support@acsol.net


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