Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!nrl-cmf!ames!lll-lcc!pyramid!csg From: csg@pyramid.pyramid.com (Carl S. Gutekunst) Newsgroups: comp.dcom.modems Subject: Re: MNP make for a faster modem? Keywords: MNP Message-ID: <13778@pyramid.pyramid.com> Date: 26 Jan 88 06:40:11 GMT References: <3027@killer.UUCP> Organization: Pyramid Technology Corp., Mountain View, CA Lines: 19 In article <3027@killer.UUCP> tony@killer.UUCP (Tony Holden) writes: >I've seen ads claiming that with the various MNP levels that the throughput >on a 2400 baud modem is that of 9600 baud. > >Is it hype or is it real? Mostly hyperbole. At level 2, MNP is slightly slower than conventional 2400bps modems because of the error correction overhead. At level 3, there is a 20% boost that results from removal of the stop and start bits; the modems run synchronously between each other. It is enough that if you set the interface speed at 4800bps, uucico sees throughput around 2600 bps or so. By level 5 you have compression, which is usually claimed to produce 4800 bps throughput. At level 6 you have more compression, and there are well chosen data patterns that will transfer at up to 9600 bps. But throughput on real data is going to be closer to 4800 bps, and on binary files or compressed data (like that from compress or pack) it could be much lower.