Why Did My OUINET Dialup Connection Drop?

A Check List
by
H. D. Knoble, Pennsylvania State University
01/02/96
edited by
S. J. Mahler, The University of Louisiana at Lafayette
11/3/99

Here is a checklist that Information Networks support personnel have customized for OUINET dialup users.

Once a OUINET dialup connection is established at a data rate compatible with your modem and serial port to UL Lafayette PPP services, the connection may drop. The following is a check list of possible reasons for this specific scenario. We recommend that you copy and check this list before calling for technical assistance if and when you experience seemingly random connection drops (disconnections). This not only will help us; but it will help you improve the reliability of your microcomputer communications. The checklist follows:

1. The OUINET dialup servers (that answer telephone numbers 482-2671 & 482-2672) drop data (i.e. the modem connection) after 20 minutes of Internet inactivity for students or 1 hour of Internet inactivity for faculty and staff. "Inactivity" is defined as no modem data exchange. E.g., using Eudora to compose a letter taking more than 15 minutes to compose it while using no other OUINET dialup clients; e.g., while connected using any Windows applications that are not OUINET dialup clients - like Word Perfect, Excel, etc. - for more than 15 minutes at a time would cause no modem data exchange and so would be considered "inactivity."

   This was done because some people were staying connected (using a Server rack modem) for hours (sometimes 24 hours) at a time, even when not using their PC; therefore many others were often getting a busy signal when dialing the Servers.

2. In addition to (1) above, when accessing specific hosts through Telnet/TN3270 the following applies: If the system you are connected with has an inactivity timer, when the timer expires you will be disconnected from the host and returned to the OUINET Dialup menu. Inactivity at the OUINET Dialup menu will cause a disconnect after 3 minutes.

3. Some PC screen savers (and some TSR's in general) do interfere with communications. Typical symptoms in this case are "random" line drops (when screen saver kicks in/out), and file transfer via FTP interrupted and aborted. We do not recommend running screen savers or other timer-related DOS Terminate and Stay Ready programs when using modems, period.

   The same problems can happen with FAX software which if loaded will interfer with data transmission. Using Fax software can also leave the modem in Fax mode; if a modem reset (AT&F and sometimes ATZ) is not done before DATA mode is used, the modem will dial a data line but login scripts will either not work at all or work with anomalous results.

4. For Windows OUINET dialup clients, a Windows GPF (General Protection Fault) may cause the connection to be dropped. Please see the file General Protection Fault Guide, available at ftp://ftp.cac.psu.edu/pub/dos/win/gpfguide.txt.

5. There are lots of external (environmental) causes for faulty modem communications, especially (but not only) for high-speed (28.8/56K) connections. Most of these are related to the phone line itself. Sometimes (but rarely) this is a BellSouth problem. More often the problem is related to the phone line between the phone jack and modem, or serial connection between modem and microcomputer serial port. Our recommendations, based on years of experience and experiments involving actual cases, follow:
   1. Do not route the phone line within three inches of any electrical cord or extension cord, or PC CPU cord, or Printer cord, or Monitor cord, or any electrical appliance or power supply. This often means taping or stapling the phone line away from such places between jack and modem. Symptoms are random dropping of the line, problems with TCP/IP clients, logging in, etc. Inductance from electrical lines wreaks havoc with phone lines.

   2. Do not route a phone line being used by a modem through answering machines. Some of the "smarter" (and cheaper) ones have been known to intercept/inject data, which of course is undesirable.

   3. Do not route a phone line underneath a carpet since people probably will walk on it, thus crushing the very fine wires therein. The same is true for running phone lines where doors will close on them, etc.

   4. Do not use old phone lines from jack to modem. Use a new phone line of the correct length, without splicing (splicers also have been known to cause loose connections, and thus problems, in some cases).

   5. For external modems, if your serial adaptors or serial cable is old, adaptor pins bent, or cable cracked, replace them. Make sure your serial connections are TIGHT. Parts (a) and (c) above above also apply to serial cables.

   6. For internal modems, and for all microcomputers in general, dust buildup on internal components compromises built-in PC cooling systems. While any PC is running, fans circulate air around internal components. We recommend that after unplugging all related electrical connections, you remove the CPU cover and carefully blow dust off all computer components, including internal modem cards, at least once a year; compressed air cans (purchased where electronic components are sold) or reversible vacuum cleaners may be used this purpose. We service University computers by request, dial TT#. Dust free components PREVENT communications problems.

   7. Surge protectors for both computer power and phone connections are recommended. But we recommend that you unplug your computer and modem during electrical storms (which may do more than interfere with a TCP/IP dial up connection). Note that typical power strip surge protectors become less effective with each surge; after three or four major surges they may not be surge protecting at all. It is possible to have a phone line surge protector installed by BellSouth which will more effectively protect your phone equipment. Most modems are quite susceptible to especially lighting surges; if your modem all of a sudden quits working after a storm, it may have been permanently damaged. One way to test this possibility is to move the modem (card) to a different computer at a different location, wiring, PC, operating system, etc and see if it works there; if not, the modem may damaged.

6. When dialing with a modem through a phone with the BellSouth feature "Call Waiting", if "Tone Block" is not activated (i.e., Call Waiting is not canceled for this call) then if someone calls after such a dial-up connection has been made, it is highly likely that the data connection will be dropped.

7. Hours of availability for the OUINET dialup are advertised as follows by Information Networks: "Normal operating hours for OUINET and the OUINET dialup are 24 hours per day, 7 days per week; 11:45 A. M. to 12:30 P.M. is the time designated for normal maintenance. Most often, the historical record shows that the maintenance period was given over to normal operations. However, normal maintenance may disrupt the OUINET dialup so no guarantees about quality are made for the normal maintenance time."

8. Parts of the Backbone, a Nameserver, Router, or Mainframe is down or was down (or hung, or overloaded) when the problem was being experienced. The Help Desk can help confirm these instances. Call them AFTER you checked out possibilities (1) thru (6) above: (1) and (2) can be monitored by being alert and using a watch; (3) thru (6) should be attended to as regular maintenance as good computing practice.

9. Finally, there may be COM Port conflicts. This can be COM Port addresses on microcomputers where COM Ports are configured with BIOS Setup incorrectly. In this case if the BIOS Setup were changed the modem may not even be accessible (won't dial).

   More often than COM Port conflicts can be IRQ conflicts. Note that with normal (default) IRQ settings, COM1 and COM3 share IRQ 4 and COM2 and COM4 share IRQ 3. This means that if you're using COM4 for an internal modem, for example, then you may not have any COM2 software (e.g., scanner) active while the modem on COM4 is being used. If you do, in general the modem won't work at all, but it may dial and then sporadically disconnect depending on a lot of factors. Detaching hardware from COM2 won't solve the problem in necessarily. Make sure there's no software (e.g., drivers, programs etc. started for a COM Port that shares an IRQ with your modem while you're using your modem.