The CoreComm FAQ (list of Frequently Asked Questions) answers questions that are frequently asked of CoreComm's technical support department.

This document is intended to help troubleshoot the most common problems individuals have with their modem connections -- low (or incorrect) connect speeds, disconnections from our system, and other related problems.

• My modem is a 28.8, 33.6, or 56k, but it connects at a lower speed. How come? Is there something wrong on your end?
• I keep getting disconnected from the system. Are you guys kicking me off? What can I do about it?
• When I log on, my modem says CONNECT 57600, or 115200. Am I really connected at that speed?
• I upgraded my older, slower modem to a new, faster external modem: and the new modem seems to be very slow -- as slow as my old modem! What's going on?
• Why do I keep getting "COMM Overrun" errors using Trumpet Winsock?
• When I log into any on-line service, my mouse freezes up. Help!

My modem is a 28.8, 33.6, or 56k, but it connects at a lower speed. How come? Is there something wrong on your end?

The term "28.8 modem" and "56k modem" is a bit misleading. A more appropriate name for a high-speed, v.34 modem is "28.8 capable modem" or "56k capable modem". A v.34 or 56k modem does over 2000 line tests when it establishes a connection to determine the maximum speed of the connection that you're using.

The maximum speed that your phone line is capable of is a combination of many factors: the quality of the wiring of the phone connection, the distance between you and your phone company's CO (central office), the kind of switching equipment your phone company has you connected to, and the way the phone company is routing your call. When all is said and done, there are few areas that will get consistent 33.6Kbps and 53,333bps connections. The newer v.34+ and v.90 modems which support 33.6 up to 56kbps are no exception: while they are capable of handling speeds that high under optimal line conditions, the majority of phone lines will only be able to make a connection less than that speed.

CoreComm's lines are optimized for the highest speeds possible: as such, connections higher than 28.8 and approaching 53kbps are possible with our service, but only from areas that have particularly clean telephone service.

While connections at 24k or 26.4k are normal and can be expected with a 28.8 or 33.6 modem, getting very slow connections, such as 19.2k connections, may show a problem on your line. You may want to call your phone company's residential repair department for a free line test if you get consistent slow connections.

Or see our In-depth Troubleshooting article for slow connection speeds.

I keep getting disconnected from the system. Are you guys kicking me off? What can I do about it?

When using a modem to access on-line services, there will almost invariably be an occasional disconnection. If this is a chronic problem for you, this document will help you find out what's causing the disconnections, and what you can do about fixing it.

One of the most common reasons for disconnection problems is line noise. When there is extended static or noise on a phone line, or the signal becomes very weak, the two modems exchanging data can't "understand" each other. Most modems will pause when there is noise on the line and wait to recover the connection, but occasionally this is not possible, and the modems will disconnect from each other.

From USR's web site:

"Dropped connections can occur when there is a sharp decrease in line quality during a call. [28.8] modems will switch to rates as low as 4800 bps to compensate for these changes. If the loss of quality is extremely severe, they will drop the connection."

There are often severe changes in line conditions during and after inclement weather: moisture in the ground caused by storms, flooding or snowfall will typically make connections less reliable. There are many other conditions that might affect line quality: if you have tried all of our suggestions in this document and still experience disconnect problems, you may want to contact your telephone company's repair department.

For maximum line quality, CoreComm uses what are known as channelized T1 lines on most of our connections. These digital lines, similar to ISDN lines not only allow us to offer 56k service, but are also not as susceptible to the types of noise and signal problems that are common with standard analog lines.

Some older 28.8 modems are not as capable of holding connections with bad line conditions: these are known as v.FC modems. If you have a modem that supports v.FC but not v.34 for 28.8 connections, that may be the cause of your problem. You can get this information out of your modem's manual. Most modem manufacturers offer an upgrade that will allow you to upgrade your v.FC modem to a v.FC/v.34 compatible or even to the new V.90 standard; contact your modem's manufacturer for details.

Also, there are often occasions where the firmware for a particular modem (i.e., the software that "runs" the modem) is prone to disconnects. In the past, problems of this sort have appeared with Supra firmware upgrades to turn their 28.8 modems into 33.6 modems, and on early X2 modem models. If you are experiencing disconnects and have either a new modem or recently updated your modem's firmware, you might want to check with your modem manufacturer to see if a fix, updated firmware, or updated software has been released.

Another common reason for lost connections is call waiting - the call waiting "beep" on the line is interpreted by modems as noise on the line, and can eventually cause a disconnection. In most areas, you can turn off call waiting by adding *70, before the CoreComm phone number (if this does not work, check with your local carrier about the procedure to turn off call waiting while on the Internet).

Inactivity can also cause disconnections. CoreComm has a 20 minute inactivity timeout, meaning that if you do not send any data over your Internet connection for twenty minutes, your connection will be dropped. When you type a message in your mail program (say, Netscape or Eudora), it's not actually sending any information out over the Internet until you actually click on the send button to send the final message out. Most Internet dialer programs will automatically drop the network connection after a few minutes of inactivity. The best way to get around this is by using a "ping" client, which will send small, unobtrusive packets of data across the Internet to keep the connection alive.

Windows 95, 98, and NT4.0 all include a ping client: you can use it by opening up a MS-DOS Prompt and typing in 'ping -t core.com' and hitting enter. Minimize the window, and your connection will remain active.

If the disconnections are occurring at times when you're certain you're not inactive (such as file transfers), the problem may be linked to the hardware handshaking configuration of your modem: try adding &K3 to your modem's init string to force this feature on.

If you are connected for over 8 hours, you may be disconnected in order to be fair to our other customers. Simply dial back in if you need to continue to use the system.

Also, by default, all dial in accounts only allow ONE concurrent connection online. So, if you are online your account, and someone else tries to log on with your account, you may get disconnected. Make sure you are the ONLY person logging on to your account and you should be ok.

Some modems are better than others at holding connections. We've rarely seen problems with US Robotics brand modems (except one particular model -- see the section on RPI below) or Motorola's. Modems that use the Rockwell chipset. However, some are more likely to sporadically disconnect: modems by Hayes (esp. Hayes Accura), Zoom and Practical Peripherals, and software modems, such as the LT WinModem and HSP modems are more likely to experience problems of this sort.

Other modems, known as RPI modems, don't have error correction built into the modem: you need special RPI drivers. If you have an RPI modem -- the two most common are the USR Sportster SI (not to be confused with the standard Sportster FaxModem) and the Zoom 14.4 PC -- but aren't running the WinRPI drivers, that's likely the problem.

Some older cordless phone and fax machines use capacitors, which are prone to send surges of electricity across the phone connections that those units are attached to: such a surge can easily knock a modem user off-line. If all of the above measures have failed, you may want to disconnect all of your other phone and fax equipment from the line for testing to see if possibly one of your other telecommunication devices is knocking you offline.

Need more information? Check out our In-Depth Troubleshooting article about Unexpected Disconnections.

When I log on, my modem says CONNECT 57600, or 115200. Am I really connected at that speed?

The CONNECT message that your modem reports can be one of two things. The first, known as the DCE ('Data Communicating Equipment') speed, reports the actual connection speed between the two modems across the phone lines: the maximum speed available with current analog modem technology and phone lines is 53333bps. However, your modem could instead be reporting the DTE ('Terminal Equipment') speed, the speed at which your computer is sending information to your modem. The DTE speed can be 19200, 38400, 57600 or 115200 on most machines.

If you want your modem to report the true connection speed (i.e., the DCE speed), on most modems it is as simple as adding the string W2 to your modem's initialization string. If that is not the case, consult your modem's manual for details. If you are using Windows95/98, using a different modem driver may also change whether dial-up networking displays the DTE or DCE speed.

I upgraded my older, slower modem to a new, faster external modem: and the new modem seems to be very slow -- as slow as my old modem! What's going on?

External modems rely on a serial chip inside your computer for the transmission of information across the serial interface between the computer and modem. Unfortunately, older PC clones may have a serial chip that simply can't keep up with a 28.8 modem. The 8250 and 16450 serial chips are only reliable up to approximately 9600 baud: meaning that they'll work fine with older, slower modems, but not with 28.8's. The 16550 chip, on the other hand, is reliable up to 115200.

Windows 3.1 users can check to see if you have an older 8250 or 16450 serial chip in the MSD program. Drop to a DOS command line, type MSD, and select "COM Ports". Under the COM port your modem is on, check the "UART" setting. Is it 8250, 16450, and not 16550? If so, you'll want to get a new serial card, one that supports the higher speeds.

If you don't have the MSD program, check with your computer's manufacturer about the type of serial chip used in your machine.

If you have an internal modem, you don't need to worry about the uart, or kind of serial chip your computer has. Internal modems come with their own high-speed serial chips.

Why do I keep getting "COMM Overrun" errors using Trumpet Winsock?

The most common reason is discussed in the answer above. If you've got a high speed modem (14400 or higher), make sure that you're using a 16450 or 16550 UART, as opposed to the older 8250 UART.

If you're using Windows 3.1, you might want to check a few settings in your system configuration file. To do this, open your File Manager and select File -> Run. On the Command Line, type "sysedit" (without the quotes) and click Ok. One of the windows that opens will be system.ini. This is the one we want. In here, check the "comm.drv=" line in the [boot] section of your that file. If it reads "comm.drv=comm.drv", you are probably using the original comm driver which was designed for the 8250 UART.

If that doesn't help, try adding the following statements to the [386Enh] section of your system.ini file:

comXfifo=1

comXbuffer=1024

comboosttime=8

Where X is the number of your COM port (most often COM 2).

Some video drivers built around the s3 video chip also hold CPU cycles and therefore cause overruns as well. s3 has apparently released driver updates that cure the problem. Several OEM vendors using the s3-based design have also followed suit.

Unfortunately, there is one cause of overruns that cannot be avoided... When accessing local disk(s), Windows halts any I/O to the comm ports for a short period of time. This in turn causes the overruns, when the Winsock is unable to access the comm port. This is unfortunately a glitch with the internals of Windows.

When I log into any on-line service, my mouse freezes up. Help!

This indicates that your modem and your mouse are sharing the same interrupt line (IRQ) on your computer. COM1 and COM3 share IRQ 4, and COM2 and COM4 share IRQ3: meaning that if you have a mouse on COM1 and a modem on COM3, the two will conflict.

If possible, you'll want to have your mouse and modem on complementary COM ports: mouse on COM1 and modem on COM2, for example, or mouse on COM1 and modem on COM4. Some modems will allow you to use jumper settings on the modem to jump to another, unused IRQ -- check your modem's manual on how to make these changes. If you didn't install your modem, you might want to have a professional do the "dirty work".