08-20-2006, 09:34 PM
[quote sscutchen]56K modems rely on digital phone lines. These lines use 8-bits for each audio sample, and they sample at 8000 times a second. This gives a maximum of 64 kbits of data per second. One bit in 8 is used as a command bit, so the real life limit is 56k.
That is what limits the theoretical max to 56K on the digital portion of the connection from the ISP to your local office. The FCC limits on signal strength to keep the analog modem signal from interfering with adjacent pairs applies to the analog run from the office to your home. That limits the modem in practice to less than 56K. Most often you will see the speed closest to 53K as your max, but if you are on a short, clean run to the central switch then you might see 54k like Filliam.
That is what limits the theoretical max to 56K on the digital portion of the connection from the ISP to your local office. The FCC limits on signal strength to keep the analog modem signal from interfering with adjacent pairs applies to the analog run from the office to your home. That limits the modem in practice to less than 56K. Most often you will see the speed closest to 53K as your max, but if you are on a short, clean run to the central switch then you might see 54k like Filliam.