My new US Robotics 815633 USB faxmodem doesn't work

[dkace]

Hi all!
I cann't make my new modem work. Control Center of US robotics doesn't find it, I connect to the internet using the ats32=64 command, that gives me a 33.6 Kbps speed, that is v.34 modulation, and it seems that I will never exceed this speed unless somebody gives me his knowledge on this. I suspect that the problem is the COM port but I am not sure and I don't know what to do . I use windows XP Pro SP2 ( installed the day before) but the same thing was going on with SP1.
Any good ideas on this? I will appreciate it!!!
Feel free to email your suggestion !
D.

 

[jadinolf]

I have one of these modems thrown in a corner somewhere. I just hated it and my connect speed was also never better than 33.6 and as low as 1.2Kbps.

 

[Peter]

It's not ON a COM port. Its driver software is pretending to BE a COM port. It's supposed to be like that.

You need to set the virtual COM port's speed up to 115200 at least, else no V.90. When you've done that and you still don't get V.90, you should start questioning the quality and correctness of your house's phone cable wiring.

 

[dkace]

Well, I don't know about the line but the com speed was ok 115200. It still had the same problem and the place I bought it took it back and gave me a Tornado 565. The saleswoman noted that she had excactly the same problem with a different motherboard than mine. She didn't even look in the box to see that the modem was in and ok!!!
Anyway the question is alter as follows: Does anyone knows a programm to test the capacity of my phone line? Is there a way to do this? I now connect on a speed varying from 49 to 55 Kbps but I think that this is not the true value. Any suggestions?

 

[Peter]

Well yes. The most advanced equipment to measure phone line bandwidth and noise levels is called a V.90 modem They do exactly that when they "train" the best possible parameters for the connection; that's what the screeching and bleeping at the beginning of a connection is about.

Regarding your worries about "actual" line speed ... you are correct in that the INITIAL line speed isn't necessarily the SUSTAINED one. Some modems are aggressive about their initial speed, and often have to step down a bit afterwards. Others have the reverse strategy. In fact, V.90 (and V.34) have "quick step" adaptive speed as major design features, to be able to react to changing line conditions.

You'll be able to tell when you run a large download. At 50-ish kbit/s you should see sustained download speeds of around 5 KBytes/s.

 

[dkace]

Thanks Peter !!!
Modems were out of my studing corpus during my master years so, any new tip is accepted!!!
Anyway, it is true that the actuall line BW is down to 5KBps. Is there any way to clear things up? I mean can I boost my connection to match or come near the promissed modem speed? Big question I guess!
Any ideas?
D.

 

[Peter]

50 Kilo_BIT_ per second. With 8/10 encoding, 5 K_BYTE_ per second is all there is. Nothing wrong with that.

 

[Zepper]

If there is more than one D to A (digital to analog) conversion between you and your ISP, then the top you will ever get is 33.6 (or maybe even 28.8) kbits/sec. And most phone companies only guarantee 14.4 kbits/sed if that. You will have to ask your phone company about the D to A conversions. Ask them if full digital is maintained from their connection to the national backbone down to your substation.
. Your ISP should also be able to help you figure that out.
. And as others have said, always check the house wiring. I do that by wiring my modem directly to where the phone line comes into the house to see if the signal is any better. And Radio Schlock had a cheap tester that you can use to tell if the line polarity is correct. I wired from the house entrance to the jack near my computer myself so I know the polarity is right...
.bh.

.bh

 

[dkace]

Ok guys, your info on modems is quite usefull. I think I will check on my communications books for the basics. But my question - and quest- still stands: Can we boost this speed? To be more specific: Apart from the DACs and ADCs we cann't control in the network of the provider, can we clear the line using some filtering, software or hardware? can we compress information in order to achieve better speed? I understood all about the protocol and the way the user transmit t o the phone line, but can we the users do something more? So far you have suggested:
- Small and correctly coated phone cord.
- Correct settings in the modem .
Is there anything more we can do?

D.

 

[tcsenter]

- Small and correctly coated phone cord.
- Correct settings in the modem .
Is there anything more we can do?

The last I knew, US Robotics has a test line to dial into and line test application. It can tell you information about the line condition or DA/AD connections but not in all cases.

Our home, and the entire local area telco infrastructure (LATA/LATN), are less than seven years old but we can't connect at more than 33K on a good day when the stars are aligned - 28K is typical. Whether its a controller-based or controller-less modem with chips from Agere (Lucent), Intel (Ambient), Conexant, or PCTel, makes no difference.

What's annoying is that I moved a few years ago from Michigan, where the local telco infrastructure and the apartment building I lived in was not less than 30 years old. I could connect at 50K there all day long.

Call and complain to the area/regional telco that owns the lines, who probably offers DSL service and thus has no interest in seeing that people's analog phone lines negotiate maximum supported dial-up connection rates. IOW, good luck with that!

 

[dkace]

Hi tcsenter,
in my country there is no such capability. I mean complaining to the phone company etc... The question is still there. Is there any boost programm to increase my dial up speed ? I can understand now that the connection speed is a matter of correct transmition etc. But is there a software that can correct this problem- at least partialy-?
D.