Connection & Modem Help

The very first thing you should consider is whether or not you've installed the most recent drivers for your modem. Consult your hardware manufacturer for information.

Remember: Reported initial connect speeds won't necessarily be dependable or even comparable from modem to modem or location to location. The reason is that V.34 modems can (and often do) speed shift up and down after the initial connection, and do so in a manner that is dependent on the particular connection as well as the particular equipment (including firmware versions) at each end. Some modems connect at a more conservative speed and then quickly upshift as conditions allow; other modems connect at a more aggressive speed only to quickly downshift (or worse, lose performance due to excessive errors).

Ameritech considers your phone line to be within acceptable operating parameters if (among other electrical statistics) you can talk on the line with a "bandwidth" of 300 to 3000 Hz. (That is, the phone is working properly if sounds in that range come through.) This is not just an Ameritech spec, it's pretty standard throughout North America.

If you have 300 to 3000hz bandwidth, and no electrical or other problems with the line, you have enough bandwidth for a 21600 BPS connection with your v.34 modem. Connect rates higher than this mean that your telephone company is providing you connection quality "above-and-beyond" their responsibility for phone service. The phone company has no contractual obligation to supply digital throughput of higher bandwidth on regular voice lines.

Proof of the this-much-bandwidth-equals-this-baudrate argument has been provided on the USRobotics web site. You will also find much more interesting information about dropped connections and other annoyances of the Internet.

Customers seeking to increase their line quality must first understand that any requests to get the Telephone Company to improve POTS service beyond normal specs may be met with an outright "No." The phone company provides GUARANTEED data throughput for consumers, and they call it ISDN. If the phone company is willing to help, some things that can help are removing "bridge taps" and capacitors installed in the circuit to improve voice quality. The test for loss at various bandwidth levels (the critical one for modems, that detects un-obvious flaws) is called a "slope test", and is done with high-end expensive test equipment.

If you consistently connect at lower speeds (e.g., 24000 or even 21600), there may still not be much that you can do, but you can at least try the following:

If you have your modem connected to the phone line through a surge suppresser, try it without the surge suppresser. Many surge suppressers can interfere with modem communications.

If possible, test for premises problems by disconnecting all your premises wiring (and equipment) from the incoming telco terminating block, and hooking your modem directly to it. If your connections are better, you have a premises problem that you may be able to isolate and fix. Premises problems (faulty wiring and/or equipment like cheap phones and fax machines) are a frequent cause of 28800 connection problems.

If that doesn't help, listen carefully to the quality of your voice connections. Note that you must dial a known quiet number, since many otherwise good phone lines exhibit excessive noise until you actually connect. (Dialing a single digit is not enough.) After you connect, if you hear more than very faint hiss and/or hum, then you probably have a line problem.

While a quiet line is important, there are other line problems that can reduce your speed: bandwidth (frequency response), distortion, etc. It is difficult to test for these problems without proper test equipment, but it's still a good idea to listen carefully for audible problems, particularly if you can find a number that will send you test tones.

You may be able to get your phone company to improve the quality of your line. Since phone companies are often reluctant or even unwilling to work on data problems, it may help to report that you are also having fax problems. Or you can try asking for a data or fax "specialist." Ideally you want the service technician to bring the right kind of test equipment, a sophisticated line or transmission test set, not just the normal basic tester. It may also help to ask for a BERT (bit error rate tester) or "data test set."

Sometimes switching to a different cable pair from the CO (central office) will help. In extreme cases the author has resorted to ordering a new line, making sure that it is good when installed, and then canceling the old line.

You may be told that you need a special "data" line, more properly called a "conditioned" circuit, which is considerably more expensive than a standard "voice-grade" circuit. Don't waste your money. All you need is a good quality "voice-grade" circuit.

A final note: Add-on noise filters will not help -- they are the modem equivalent of snake oil. Your 28800 modem already has all the filtering it can use. An add-on filter will do nothing at best, and it may well make things worse.

The Myth of the 56k Modem.

Disconnection Troubleshooting Guide

For the most part, sporadic and persistent disconnections can be cleared up by adjusting configuration options, updating firmware and drivers and weeding out other local factors. This guide explains the most common causes and includes the most frequent solutions to disconnection problems.

Editor's Note: Keep in mind that standard telephone lines were designed for voice, not data transmissions. High speed (V.34 and V.90) modem connections push the physical limitations of any voice-grade line. Connection problems are sometimes (but not always) due to conditions on the telephone network.

Time Outs
If data isn't sent or received for 20 minutes, our server assumes you've left your computer and terminates the connection. No data is transferred while you're composing E-Mail, so if it takes you longer than 20 minutes to type a message, you may be disconnected. To avoid this, simply "do something" (load a webpage, check for new messages, etc) at least once every 20 minutes.

Software Conflict
If another program tries to use the modem without checking to see if it's already in use, you may be disconnected. Disable all programs that may use your modem, such as fax or terminal software.

Call Waiting
If you have call waiting and a call comes in while you're connected to Michcom.net, the "call alert" beep may cause your modem to disconnect from Michcom.net. To prevent this from happening, disable call waiting. This can most commonly be accomplished by inserting *70, before the number being dialed.

FIFO Buffers
Sometimes, the FIFO buffer settings in Windows 95/98 will cause connection problems. We've observed that "turning down" the buffers frequently clears up disconnections. Find your modem properties in the control panel (under "modems"), select the connection tab, and click "port settings". Set both buffers to the lowest possible setting.

Port Speed
Try setting your "maximum connect speed" to 57,600 instead of 115,200. If that doesn't help, bring it down to 38,400 and see if the disconnections go away. You'll find this setting under the modem properties in the control panel.

WINS Resolution
By default, Win 95/98's TCP/IP drivers use DHCP for WINS resolution. We suggest that you disable WINS resolution. Select TCP/IP under network properties in the control panel and push the properties button. Select the WINS configuration tab. Make sure "Disabled" is selected.

Momentary Loss of DTR
Disconnections may be caused by momentary loss of DTR (Data Terminal Ready). By default, most modems respond to a drop of DTR by hanging up. With US Robotics modems add S25=200 to your Init String, with other modems add S10=50. This sets the duration, in hundredths of a second, that DTR must be dropped before disconnecting.

Momentary Loss of Carrier
A similar possibility to the one above is that your modem could not distinguish between a line hit, or other disturbances that momentarily break the connection, from a true disconnect by the remote modem. Add S10=100 to the Init String to set the duration, in tenths of a second, that the modem waits after loss of carrier before hanging up.

Interoperability Issues
One common cause of disconnects is an incompatibility between your modem and the remote modem. No modem is completely compatible with every other manufacturer's equipment. Hardware manufacturers frequently resolve this type of problem by releasing new firmware and drivers. Be sure to check with your modem manufacturer periodically for such upgrades. Do not assume that just because your modem is new that it contains the latest firmware and drivers! It usually doesn't!

Other Equipment on the Line
Sometimes other telephone equipment in the home can cause a modem to disconnect, even if it's not plugged into the same phone jack. Telephones, answering machines, fax machines, other computers, and anything else that might be plugged into your phone line could be introducing conditions onto the line that cause a disconnection. Unplug everything except for your modem and see if the problem disappears.

Noisy Line
If there's too much noise on your phone line, you may be unexpectedly disconnected. If you suspect that this may be a problem, contact the phone company and have them test the line for noise.

None of the Above
Okay, so you've tried everything we've suggested and you're still being disconnected?
Contact tech support and explain your situation. Include as much detail as possible, including the type of modem, how long the problem has existed, how frequently you're disconnected, when you're most frequently disconnected, etc. We'll do our best to help!