Modem 56.7k send - 33.6k recieve

[agusgriego]

Does anybody know how to "switch" a modem speed to send data at 56.7 kbps and recieve data at 33.6 kbps?

ISPs do this, I don't think their modems are special in some way, or aren't they? There must be any AT command to do this...

Any help is appreciated,
Thanks in advance

[lethe]

i m not 100% sure on this, but i believe that ISPs modems are different. your modem connects to an analog line, and the ISPs use a digital phone line. analog lines can only support 56k upstream and 33k downstream.

[phatsharpie]

I forgot the details, but the consumer modems can only download at up to 56K (but a bit slower than that due to FCC regulations) and 33K upload. It does have something to do with analog and digital line signals I think...

[chenly]

Originally posted by lethe
...analog lines can only support 56k upstream and 33k downstream.

Wrong, lethe. Analog phone lines are limited in both directions by the Federal Communications Commission (FCC) to 53kbps; the "56k" modem standard is actually 57.6kbps in both directions, but this can only be achieved on a local connection, i.e., one that doesn't go through the phone company. Two computers' modems connected by a telephone cord would be an example of this. I don't know how one would go about disabling the higher speed in either direction, but modem scripts tend to be pretty simple affairs.

[lethe]

i guess you re right chenly. but i still think that the reason that your uploads are slower than your downloads is because you are not on a digital phone network, while your ISP (and the rest of the phone network backbone, unless you live in montana) is. you are on an analog line.

[Sogni]

Originally posted by agusgriego
Does anybody know how to "switch" a modem speed to send data at 56.7 kbps and recieve data at 33.6 kbps?

ISPs do this, I don't think their modems are special in some way, or aren't they? There must be any AT command to do this...

Any help is appreciated,
Thanks in advance

I haven't read the responses, but working for an ISP when we used to do Dialup I can tell you that it can not be done with regular analog modems. ISPs that are capable of 56k (well, a bit under than that) have Digital Modems – the ones in end-user computers are all analog.

We haven’t done dialup in a while so I haven’t been looking into that technology in over a year (close to two) now, but I think it’d be a lot easier and a lot more convenient just getting Cable Modem or DSL (unless you are trying to do something different)

[Sogni]

Originally posted by chenly


Wrong, lethe. Analog phone lines are limited in both directions by the Federal Communications Commission (FCC) to 53kbps; the "56k" modem standard is actually 57.6kbps in both directions, but this can only be achieved on a local connection, i.e., one that doesn't go through the phone company. Two computers' modems connected by a telephone cord would be an example of this. I don't know how one would go about disabling the higher speed in either direction, but modem scripts tend to be pretty simple affairs.

Chenly is right about the limitation by the FCC - which just seem plain dumb to me... but anyway...

But I think it goes beyond that where there's an actual physical governer of some sort in the modems themselves.

Hmmm.... I wonder if it can be modified? But it woldn't matter anyway cuz once it goes through the phone company like you said - it'll get knocked back down once before it reaches the ISP.

[chenly]

The 57,600kbps algorithms are the last ones ever for analog modems; since the telecom infrastructure isn't stable above 53,000kbps, no further development of modem (remember, modem = MOdulator/DEModulator; this is an digital-analog-digital process. The phrases "DSL modem" and "cable modem" are misnomers because these devices are pure digital devices) communication protocols. 57,600kbps is as good as it gets.