is there a way to get a constant connection speed when using dial-up? how?

Answer 1

nope...

even with broadband, T1, ur speed is directly related to the internet as a whole, (just like a freeway) if there are more people on it in ur area, it will be slower...

in general dial-up is much slower than broadband, which is much slower than T1 connections...

-o

Answer 2

No. The impedece on the wire of the local loop to the phone company will vary slightly due to temperature, wind or whatever. So the analog modem's negotiated best speed will vary.