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CPS - Article
 
GOT A MODEM PROBLEM?... HERE ARE A FEW TIPS

 

If your modem is taking more than 15 seconds, after the other modem answers, to train up (handshake with another modem) and/or you are only getting about 26 Kb or less out of your 56 KB modem connection... then you have a problem.

The problem may be:

  1. your house wiring,
  2. the quality of the phone line,
  3. or an incompatibility between the modems.

Here are a few suggestions that you might try to determine the source of your problem. Once the problem is determined, it may be correctable.

1. House Wiring Problem?
To determine if the house wiring may be the problem, take your computer to the D-MARK (where the phone line enters the house) and connect it there while disconnecting the house wiring. If it is easier, you can run a test cable from that point straight to your computer, but be sure to disconnect the house wiring. Now if you train up quicker and/or get a better data rate, then the problem is in the house wiring.

To correct it you can look for the problem in the house wiring (cross talk caused by having two lines in the same cable, unterminated long loops, phone cable too close to AC wires, microwaves, refrigerators, motors etc.). Or you can run a new line from the D-MARK straight to your computer (similar to the test cable, but for a permanent installation go through an isolation splitter ($85.00 and up) since you may also want to use your phones. Put the computer in one port and the house wiring in another port.

2. Phone Line Problem?
To determine if it is a phone line quality problem, go to another location; a friends house or at work and try to dial from that location. If this provides increased performance, call your phone company and ask them for a better line. It won’t do any good, but you can try. Also look for radio towers in close vicinity. They can interfere. Sometimes the radio signals can also be heard when you lift the receiver. The phone companies have filters that they can install to correct this situation.

3. Incompatible Modems?
When the idea of connecting at speeds of 56 KB over dial lines was first introduced (before the V.90 standard); competing manufactures proposed two different approaches. K56Flex which was developed by Motorola and backed by Rockwell (modem chip supplier) and the X2 approach that was developed by U.S. Robotics. There were also a few others, but this was a high stakes game aimed at influencing the standards committee as to what should be incorporated in the yet to come V.90 international standard, and they withered on the vine (politics).

Each modem manufacturer incorporated one of these two major approaches and some even used both. When an incompatible X2 modem tried to talk to a K56Flex modem, or visa versa, they would both fall back and connect at an older slower speed standard (V.34bis at 33.6 Kb or even V.34 at 28.8 Kb); not at the 56 Kb that each would support if they were talking to one of their own. The V.90 standard was supposed to resolve this, but different modem manufactures implemented it differently and there can still be problems. Add to this the fact that some ISPs still do not have V.90 type modems.

The long and short of it is that you may have an incompatible modem problem. To correct it, first go to the manufacturers web site and try to upgrade your modem to V.90. Don’t forget the modem drivers in the PC, too.

You can also determine which approach your modem supports (K56Flex or X2) and call your ISP to see if they support it. AOL has had different phone numbers in different parts of the country to support each.

You may get a "V.90 standard" run-around, but it is certainly worth a try.

Generally, AT&T, Lucent and Motorola, and most of the others support the K56Flex approach (Rockwell chip sets) whereas, 3 Com U.S. Robotics supports the X2 approach.

 

Computer Peripheral Systems, Inc.
5096 Bristol Industrial Way, Suite B
Buford, GA 30518
Sales
1-800-888-0051
8:30 AM - 5:30 PM EST
Technical Support
(770) 945-0643
8:30 AM - 5:30 PM EST
Fax
(770) 945-9342
E-Mail
sales@cpscom.com


© Copyright 1996-2003  Computer Peripheral Systems, Inc.
This file last modified February 14, 2001