Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!pacbell.com!ucsd!sdcc6!sdcc6.ucsd.edu!cg108dbd From: cg108dbd@icogsci1.ucsd.edu (Steve -Social Hacker) Newsgroups: comp.dcom.modems Subject: Re: Using High Speed Modems Message-ID: Date: 23 May 91 04:14:10 GMT References: <28675@uflorida.cis.ufl.EDU> <6536@vela.acs.oakland.edu> Sender: news@sdcc6.ucsd.edu Distribution: na Organization: University of California, San Diego -- Cognitive A. I. Lines: 58 In-reply-to: rdthomps@vela.acs.oakland.edu's message of 22 May 91 22:21:30 GMT Originator: cg108dbd@icogsci2 --=}>> On 22 May 91 22:21:30 GMT, rdthomps@vela.acs.oakland.edu (Robert D. Thompson) said: In article <6536@vela.acs.oakland.edu> rdthomps@vela.acs.oakland.edu (Robert D. Thompson) writes: RDT> In article <28675@uflorida.cis.ufl.EDU> wardc@banana () writes: >I received a little information regarding high speed transfers. > RDT> [...] > >Regarding the transfer rates for compression. One observation made was >whether the modem was being sent data fast enough to bother with >compression. The source/dest's are 286 using the 38400 bps transfer RDT> [...] RDT> I have a related question... RDT> Do modems with V.42 compression cause compressed files (e.g. RDT> PKZIP, LHARC, etc...) to become effectively larger when RDT> transferred? In other words, is there negative compression RDT> when transferring a compressed file via V.42? RDT> Thanks. RDT> --- RDT> Robert Well, I am no expert, and have just started using my HST w/ V.42. I have yet to see V.42 slow things down, and I usually transmit .ZIP or .GIF files, which are very compressed. My usually xfer speed is 1600-1720 bytes/sec on large files. (>200K) 1730 is the highest I have ever seen (last night :) and it rarely drops below 1580 (multi-node BBS's mostly). With V.42 off, the speeds are much closer to 1500 or so (1400-1550?). In the USR manual, it states that V.42 can _not_ take longer than non-V.42, and I am inclined to believe it. Oh, I have transfered a files-list that was NOT compressed (about 30K) and the transfer speed was 2650 bytes/sec and rising when the transfer finished! Wow. I have the DCE-DTE link locked at 38400 baud and am using ProComm+ v2.0, and have had similar results with DSZ. Of course, you mileage can, nay, WILL vary, so take this all with a grain of statistical salt. I have had no need to use MNP[1-5], so I can't comment there. Hope this helps. Good Luck! -Steve -- }>> Steve Haehnichen <<{ shaehnichen@ucsd.edu Disclaimer: UCSD and I do not share any opinions.