Modem configuration can be tricky business, which is the reason we felt it was important to make this troubleshooting guide available to you. However, we realize that additional help may be necessary to help you resolve some modem problems. The World's Customer Support staff is available via telephone or email if you need more help. Please don't hesitate to contact us!
It is possible that you will run into an occasional problem trying to connect with The World's modems. It could be our problem, and if it is please let us know what you have experienced so we can tend to it as quickly as possible. This guide presents common scenarios that may impact your modem's ability to connect with The World's modems, as well as solutions to the problems that these scenarios can generate.
-No sounds, nothing happens -Our modem doesn't answer -Difficulty negotiating the handshake using 14.4 faxmodem -Difficulty negot. the handshake *not* using 14.4 faxmodem -Lots of line noise or general trouble connecting -If our modem picks up, but you hear no noise at all -Broken connection after login achieved and held for some time -Upon connecting, and login, random garbage appears -Disconnected session -You've been connecting at different speeds than you used to
-8N1 (as in 8 bit, no parity, 1 stop bit)
-the communications software should be set to vt100 terminal
emulation (if its set to vt52 or something, you won't get full
screen size required by various software used on The World)
-If parity is set to e71, then after typing the login name, the
cursor jumps back to the "l" in "login' and freezes there.
Make sure you are setting to 8N1.
-If parity is set to e72, all *seems* well, but will get "login
incorrect" response. Set to 8N1.
-Hardware Flow Control (CTS or RTS) is enabled, and Software Flow
Control (XON/XOFF) is disabled. Note: most 2400bps modems
do not support Hardware Flow Control. However, some do -- typically
the documentation will mention MNP5 prominently on those.
-If the problem is at our end, we need to know which number you were trying to dial in to, and what time of day it was.
-if you've tried repeatedly and gotten ring no answer, The World's modems could simply all be in use! Keep trying. -if The World's modem is not answering- please call the same number by hand (using the handset, not the modem) and report it to us if it does not pick up then either. If The World modem picks up and yours isn't making any noise at all, you may want to reset your modem. -if you have to try repeatedly before a connection is achieved- This solution can be particularly helpful if you are using a 2400bps modem: try disabling the negotiation on your modem (ie lock the speed setting) and let The World's modems manage the negotiation. This will give the modems less chance to be confused. Different modems use different commands to do this and you should cross check any suggestions we make here with your modem's documentation. For example that is what the s37=11 does (see #6, below).
-This can help to establish whether the problem is occurring with your modem or with a particular World modem pool.
-no sounds, nothing happens- if a World modem picks up and nothing happens, which is pretty rare, check to see if your modem's speaker has been turned off. If it is turned off, you may be succeeding at connecting, but not hearing it happen, and the connection times out ("No Carrier") when you don't give some command to continue the login. To turn on the sound, you can typically use "atl2m1" in the init. string. -World modem doesn't answer- this could mean that one of The World's modems isn't working correctly and needs to be. It would be helpful if you could call the same phone number by hand (using the handset, not the modem) to check that our modems are, indeed, unresponsive. -difficulty negotiating the handshake using a 14.4 faxmodem- try the init. string atn0s37=11 (add it to the end of your current string, or set it in a prefix, if your software uses prefixes, for dialing into the World specifically, so as to avoid affecting your connections to other sites, if any.) -difficulty negotiating the handshake *not* using 14.4 faxmodem- try the string: ats10=50. This resets the timeout tolerance for absence of carrier detect (so you can try to extend the handshake for longer, bettering your chances of connecting) Specifically, the string gives 5 seconds, as opposed to 1.4 seconds, which is standard, for the handshake attempt. -lots of line noise or general trouble connecting- make sure that Hardware Flow Control(also called CTS(ClearToSend) or RTS(ReadyToSend)) is turned ON and Software Flow Control is turned off (the Xon/Xoff designation) Note: some older 2400 modems do not support Hardware Flow Control. Alternatively, line noise occasionally occurs due to a physical corrosion of the cables set up by the phone company, located in your home. Scrubbing the gook and rust off of these cables has been known to resolve some line noise problems. -broken connection after login achieved and held for some time- increase your modem's tolerance for absence of carrier detect by assigning a number to register 10, for instance: S10=50 Also, sudden knockoffs like this can be caused by compression, if things are working too *well*, try turning compression off in your modem, with: %C0 Alternatively, call waiting might allow a call to come though while connected to your modem, which will break the connection. Check to see that error correction is enabled. Check to see that retrain is enabled, which will drop the modem speed if things get bumpy. -upon connecting, and login, random garbage appears- try power cycling the modem on and off again. And then try reissuing the factory settings with the command: at&f0 -if you connect but experience random characters spewing around- These symptoms occurs if the screen size is set to 38 columns. Resize to 40 columns using one of the following two command sets:
world% stty rows 80 world% stty cols 40 or world% resize
-Disconnected session - is it possible that another member of your household has picked up a different handset while you were logged in? This could break the connection. Do you have call waiting? If so, and another call came in while logged on, that would have disconnected your session. You can add *70 to your "at" string, which will disable call-waiting for the current session only (when you log off, call waiting will be enabled again) -Youve been connecting at different speeds than usual. Double check that your line setting to your modem didn't its been connecting at mysteriously). Most modems will auto-sense the line speed the AT commands come in at from your comm program and won't offer (our end) to connect at anything faster than that line speed. Should be easy to check, as a first thing.
If you are using a 2400 baud without MNP5 (lowest level of error correction), you may have ongoing trouble due to poor phone facilities around New England. If you are using your low-speed modem with other low-speed modems, all seems well. But when your low-speed modems try to talk to our higher speed modems your modem simply loses its ability to manage. Best bet, if using 2400 baud with no error-correction should throw it away! And instead buy anything v.32bis (protocol that the modem speaks).
If you are at 14.4, your modem can likely handle data compression and can connect at 19.2.
-There is a modem setting that controls whether or not the modem (re)sets the serial line to the same speed as the connection, if your package is at 19.2 and it sets it to 14.4 when you get a connection you'll see garbage. There should be a setting in the modem itself (an AT command) that says lock the serial line speed (the line to your computer) to whatever it receives the first AT command at (the modem can tell), or alternatively lock it down to 19.2 or some known speed. It doesn't have to match the connection speed between the two modems (e.g. 14.4), but the serial line should be the same or higher than the modem-to-modem speed, and of course the same as your comm package, try 19.2 or 38.4.
If you are using a Supra or Zoom 14.4 faxmodem (or anything but USRobotics or Global Village), try changing your initialization string. Add atn0s37=11 (N=zero, S37=eleven)
-what the atn0s37=11 init. string does- This instructs the modem to not try to auto-sense speed (N0) and sets the modem's speed to 14,400 (S37=11), you ought to confirm those in your manual, they should be the same for any 14.4 modem based on that chipset.
-how to set the string- The string should be added to the *end* of the init string -- if it's followed by &F, for example, that would override it and it wouldn't do any good.
-setting this string if you use other services-- While this init. string works fine for connecting to the World's modems, may be incompatible for your connections to other sites. You may have options to set a prefix for World dial-up, and if so, you can put this init. string there. If your comm software lets you add a different init string for various services, and you don't have problems with other services, make the init string World-specific. If you call somewhere else that only has 9600 baud modems, for example, locking your modem at 14.4 like this would keep you from connecting to it.
-try adding atn0s37=9 to your initialization string. -see 'what the string does' and 'how to set the string', #8, above.
-transmission speed too fast for hardware, data lost- To get the most out of a high speed modem you need to set your serial port speed (baud rate) to faster than the modem rate. Optimally, you want baud rate in communications software to be four times the modem speed (e.g. 9600 baud = 38,400, 14.4= 57,600) and the modem serial port locked at that speed (should be the default, except some Global Villages, see #11, below). That is, do not allow your modem to change the speed of its own serial port.
For most high-speed modems, make sure that hardware (RTS/CTS) flow control is on in the software and modem and that software (XON/XOFF) flow control is off.
If you are, you may experience symptoms such as disconnects, CRC errors when transferring files, or unreliable negotiations.
Try turning off software flow control (XOFF) and enabling hardware flow control (CTS/RTS).
A common solution is to make sure the serial port speed setting is 19.2 and not 38.8. Despite the fact that software offers 38.8 speeds, not all computers have fast enough hardware to use it at that speed. This solution has proven effective with numerous customers using Windows based software.
9.1 If you are using an external modem, some older systems have
serial ports that can't keep up with our high speed modems.
Specifically, problems will occur if you do *not* have a
16550-based serial port, solutions:
-short term: lower your serial port speed to 19.2
-long term: Purchase a 16550 serial board ($50 or less)
9.2. If the version of Windows you're using
-is 3.0, its best to upgrade because it has to run at 9600 or less
-is 3.1 should be able to lower your speed to 19.2 (also
should have 46 or better CPU processor, can get a replacement
driver: VxD to improve serial io considerably).
9.3. If your communication's software is cheap, it may be unable
to handle high speed connection activities. You may have to buy
something better.
11. Are you using a Global Village PP Gold modem:
There is a known problem with GV PP Gold modems. Irrespective
of what data rate you set in your communication software the
modem will communicate only at 9600 baud or lower. Enter the
following init string and it should work the way it ought to.
1. Start you comm software, for example zterm
2. type "at &f1 &w" (don't enter the quotes).
if that doesn't do it then try "at &f %c1 \n7 \q3 \j0 \v2w1"
Both really do the same thing. If yours is one of the earlier
modems then it may not support "&f1"
3. To reset it to the factory default type "at &f &w"
12. Common problems created when you upgrade your modem
If you have recently upgraded your modem, for instance from a
2400bps to a 14.4kbps and you aren't achieving the connection
or speed that you anticipated a new modem would provide
-you may need to examine your modem configuration from top to
bottom. Simply connecting a faster modem won't often do it,
double-check your basic settings (see #1).
-if you are using the same serial port used with your slower modem,
you may need to upgrade it as well, as it may not be able to keep
up with a faster modem. Consider purchasing a 16550 serial board
13. Special Problems, Special Solutions
-If All Else Fails- reset your modem, software, and computer to
confirm that the problem is re-occurring. Despite our best efforts
computers and modems do mysteriously reconfigure themselves.
-Macs using old cables -
for some Mac users, using an old cable with a new modem, the
hardware flow control might not work. New wire comes with newer
modems that wasn't supplied with older ones, just fyi.
-For telebit v32bis (14.4) modems, turn off compression if
you are having problems connecting (the command to do this
is probably %CO in init string, but you should check doc.)
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