Re: 57600 modems

Rob Raese (bigcat@interaccess.com)
Wed, 27 Nov 1996 15:01:33 -0500


my understanding is that there are basically three factors that determine
the speed of transferred data:

1. the size of the "pipes" (bandwidth)
2. compression/decompression of the data packets by the modems involved
3. the "cleanness" of the connection (ie, noisy line, % of lost packets, etc.)

the big difference between a 28.8 modem and a 57.6 modem is that the latter
has better compression code, and better code to prevent packet loss. This
makes transfers faster because:

1. the amount of information "packed" into the signals is greater
2. the packets are compressed/decompressed faster by the modem
3. more packets are tranferred intact and don't need to be re-sent. (better
error correction code.)

the "bps" rate you see when downloading something is NOT about how fast
packets are streaming into your modem, it's about how many packets your
modem is decompressing per second.

therefore, to get the maximum "yield" from a 57.6 modem, your service
provider must also be using a modem with the same kind of improved code.

that's my understanding anyway.

::::::::

"My rods and cones are all screwed up!"

- Kramer