jpr@dasys1.UUCP (Jean-Pierre Radley) (06/02/89)
In article <1182@wpg.UUCP> russ@wpg.UUCP (Russell Lawrence) writes: >In article <49@wells.UUCP>, edw@wells.UUCP (Ed Wells) writes: >BTW, Ed mentioned in a previous article that he was unable to get his >TB+ to work faster than 9600 on outgoing calls. My uucico supports >19.2 kbs calls, but I've never (ever) been able to get a throughput >of more than 700 bytes per second. One of my net neighbors thinks >the problem might be line noise, but I'm beginning to suspect that something >else is wrong. If anyone else has encountered a similar problem, how >about sharing the solutions? The calling computer must be running at 19200, and also the receiving computer. On the dial-out port, stty should reveal a speed of 19200. On the receiving computer, the gettydefs for the receiving port should also be at 19200. CPU <-@19200-> TB <-@9600-> telephone lines <-@9600-> TB <-@19200-> CPU Each computer talks with its trailblazer at 19200. Each trailblazer talks with the telephone line at 9600. The faster throughputs, up to 1700 or 1800 bytes/sec, occur on ASCII files, or data files with lots of blocks of nulls or spaces. The trailblazers can compress such files while in PEP mode. Files which are already compressed, or most binary files, will not transfer at such a rate. -- Jean-Pierre Radley CIS: 72160,1341 jpr@jpradley.UUCP
chris@netcom.UUCP (Chris Lakewood) (06/03/89)
In article <9858@dasys1.UUCP> jpr@dasys1.UUCP (Jean-Pierre Radley) writes: >CPU <-@19200-> TB <-@9600-> telephone lines <-@9600-> TB <-@19200-> CPU ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >Each computer talks with its trailblazer at 19200. >Each trailblazer talks with the telephone line at 9600. >The faster throughputs, up to 1700 or 1800 bytes/sec, occur on ASCII files, >or data files with lots of blocks of nulls or spaces. The trailblazers can >compress such files while in PEP mode. >Files which are already compressed, or most binary files, will not transfer >at such a rate. >-- >Jean-Pierre Radley CIS: 72160,1341 jpr@jpradley.UUCP Wrong. The two modems communicate using PEP at varying speeds up to 18,000 bps. The content of the data (i.e. binary vs. ASCII) has NOTHING to do with the speed at which the modems communicate. An extension to PEP called PEP2 supports data compression and can achieve speeds of 19,200 bps on compressible data. It is not uncommon to see speeds of 1400 characters/sec or more on data that is ALREADY compressed. This is where Telebit is way ahead of the other "high-speed" modem makers. Their claims of 9600, 19200, or 38,400 are based on sending data which is highly compressible. If the data is already compressed, their thoughput goes WAY down. Please check you facts.
hamilton@osiris.cso.uiuc.edu (06/05/89)
chris@netcom.UUCP says: > It is not uncommon to see speeds of 1400 characters/sec or more on > data that is ALREADY compressed. This is where Telebit is way ahead > of the other "high-speed" modem makers. Their claims of 9600, 19200, or > 38,400 are based on sending data which is highly compressible. If the > data is already compressed, their thoughput goes WAY down. > > Please check you facts. i can't speak for all high-speed modems, but my old HSTs routinely got ~1100 c/s on already compressed files, and my new HSTs (50% faster) get over 1600.
dag@fciva.FRANKLIN.COM (Daniel A. Graifer) (06/06/89)
I have a pair of Prime EXLs that were running ATT SysV 3.0 hdb uucp over TB+ long distance (VA to CA) and routinely achieving 1400cps. Recently, the VA machine was upgraded to 3.1, and uucico at 19,200 stopped working. I can only get garbage unless I slow down to 9600. This is true when I call uunet as well. Prime says they are aware of this, but cannot tell me why. Anybody have any ideas what they broke in this release? FYI, 3.1 was the release of "Network Support Utilities" and the routing of everything thru STREAMS. Thanks in advance. Dan (Note, use address below, "Reply" may not work.) ------ Daniel A. Graifer Franklin Capital Investments uunet!fciva!dag 7900 Westpark Drive, Suite A130 (703)821-3244 McLean, VA 22102