how to tell if my dial up modem is going bad?

[zoldos]

I have a generic v.92 56k dial up modem. For the past couple months or so it has steadily declined in connection speed. It normally connected at 40k but then it was 38k, then 36k, then 33, 32, sometimes 21 or 25. I changed the PCI slot it is in with no effect. I also changed the phone cord and still the same. I called my ISP while it was connected and they said everything looks fast, no problems on their end. I also noticed when it is connecting, it sounds like it is finished making the usual sounds dial up modems make, but then it repeats all the sounds over again. When it does that, it always connects around 21.6k. I have yet to get it to connect at 40k again.

Could the modem be going bad? Could buying a new one help me connect faster? Any help would be greatly appreciated. Thanks!

 

[goombawaho]

I would focus more on the phone line and that there is phone line noise that is causing the issue. Can you get your line checked by your provider just to prove that it's clean??

Then look for a diagnostic test for your modem from the manufacturer.

 

[edfair]

You could have stuff going out of tolerance and failing to connect the same way. You could also be having line problems.

You might try a low pass filter and see if it helps. They correct a multitude of noise issues.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[webrabbit]

You could have malicious code which disconects from your regular isp and makes a long distance call to another isp. I had this happen to me several years ago. You should check your phone bill for suspicious long-distance calls you are not aware of making.

 

[zoldos]

goombawaho: There doesn't seem to be any noise on the line and the line is fairly new (they ran a new one just for our internet use). I will look for some diagnostic software.

edfair: It is possible but it connected at 40k every single time for at least a year up until a few months ago and nothing hardware wise has changed and I'm still using the same ISP. I have a surge protector that I used to run the modem line thru. Is this a low pass filter?

webrabbit: No, everything is fine on the bill and we don't even have long distance available, and I've tried several other dial up numbers with no change...

 

[edfair]

One of the things you can do is pull the phone line out of the surge supressor. They can create the problem. Your phone line probably has a built in surge supressor at the demarc. Most do. And those also can cause grief.

A low pass filter is a different device. Passes voice band frequencies but blocks higher than voice band stuff. Costs about $10 at Radio Shack or electronic store. Or if you have a buddies with DSL one may have an extra DSL filter, which is the same thing.

Is the phone cable passing near something with a switching supply. Or near a fluoresent light. Some are also critical on the length of the satin line cord if there is a noise source close. (electrical noise)


Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[webrabbit]

Do you have call waiting? Sometimes the call waiting signal will cause a drop-out, and your browser software may be smart enough to reconnect after dropping the speed in an attempt to avoid another drop-out. If you do have call waiting, there is a code provided by your telephone company that will temporarily disable it prior to making a call. That code can be entered into your isp dial-up string.

 

[zoldos]

edfair: I no longer have the phone line running thru the surge protector. I may have an extra DSL filter laying around that I can try. The only thing it runs near is a TV (about 4 feet away) and then right behind my LCD monitor. I don't know if these qualify as a switching supply.

webrabbit: I don't have call waiting but I do appreciate the tip!

 

[goombawaho]

I didn't know anyone used modems any more. Only see 1 or 2 per YEAR in my work!!!!

 

[webrabbit]

Regardless of the reason, the fact that your modem is reconnecting at a lower speed indicates that the connection was lost for some reason. So the question is, why is the connection being lost.

From your inital post, it seems as though the connection is only being lost immediatly after being established. Is this correct?

The only two reasons I know why a connection is lost is a noisy line and a break in the connection such as call waiting, another extension being picked up, or a short or actual break in the line. As your isp says the line is clean, that eliminates the noisy line as a problem. I got the impression that the line is dedicated for computer use, and another extension is unlikely. So what's left is a short or break, which could be anywhere: line cord, house wiring, connection at the pole, etc.

If the lost connection is only at the beginning, that eliminates an intermittant short or break, so what's left? Nothing I can think of, except a poltergeist.

 

[zoldos]

It stays connected just fine, and will stay on-line for 24-48 hours before disconnecting for whatever reason. What I meant is that when I decide to get on-line, it will connect at lower speeds than before.

For example, for the first year we had the dial up account, every time we dialed in, we'd connect at 40k. But starting say 2 months ago, when we dialed in, it would be 36k. The next time, 33k. I'd disconnect manaully and reconnect to see if I can get it to go higher, and sometimes I can get it to do 38k. Or sometimes 32k and even as low at 21k. If I keep disconnecting and reconnecting I can get it to go higher.

I ran a modem diagnostic program that I got from the modem company's offical site (it is an Agere Systems PCI soft modem it turns out) and everything checks out.

The only thing left to do is try a low level filter, but remember the original question: Is the modem going bad? If I buy a "better" modem, will it connect at higher speeds?

 

[webrabbit]

Perhaps you should try a new modem. They're cheap.

 

[edfair]

At the initial connection the modems talk to each other to figure out the highest speed that they can reliably connect. So, for whatever reason, they can't talk at 40K any more. Internally they have to decode tones which are analog signals and subject to all sorts of distortions that will affect the ability to do the decoding and therefore the speed.

Diagnosing the problem can be a bear.

It can be your modem, and a new one MIGHT connect at a higher speed. But might connect at even a lower speed. No way to tell. Or you could try an external, but you are subject to the same issues. The UNIX boxes I supported had external USR modems and I locked them to 9600b as that seemed to be the highest I could expect regularly. One has recently gone flaky at that speed, but considering the 50KW commercial tower about 100 yards away and the landline circling around it I'm not surprised.

You could attempt connecting to other modems. Other ISPs should still have dial-in and should connect even though you don't have login credendials. That would test the modem's ability to connect at higher speeds.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[zoldos]

Well the last thing I have left to try is a low level filter I suppose. We don't have the best phone lines but it did connect at 40k for quite awhile....

Thanks for everyone's suggestions and feedback, it is most appreciated!

 

[jkl0]

If you have access to the phone company's phone box, there is a phone jack located inside the box that is used for test purposes. If you can run a direct line to the box, you can check to see if that makes any difference. If it is faster from there then you can assume that the problem is with your home wiring.

J.K. Long

 

[zoldos]

The line is brand new as we just had it put in. I was able to connect at 36k and other speeds so I'm not too worried about it now that it seems it isn't the modem. We have old lines down the street and since we live in the country it takes them forever to realize they need to be upgraded!

Thanks for the reply!

 

[edfair]

They hate replacing cable. Up until about 5 years ago I had a stretch of 1938 cable between me and the CO. It tended to get noisy from seeping water and they kept swapping pairs around to resolve my problems. They finally replaced it.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[zoldos]

Yup, pretty much. I don't know how old the main lines are, but I do know they won't support even the slowest DSL...