greg@ntvax.UUCP (07/08/88)
MNP - Question
Does anyone have anything outlining the specifications for the
MNP modem protocols (Level 1-7) ?
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---------------------------------------------------------------*/davidsen@steinmetz.ge.com (William E. Davidsen Jr) (07/11/88)
In article <27800001@ntvax> greg@ntvax.UUCP writes: | | MNP - Question | | Does anyone have anything outlining the specifications for the | MNP modem protocols (Level 1-7) ? Levels 1-4 are public domain, and anyone with a a copy can duplicate it for you. I don't have a machine readable copy, and the hardcopy is a bit large for duplicating and mailing (a lot large). You may be able to get the info from Microcomm (sp?). It will have to be duplicated by a real print shop and mailed, I'm afraid. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
david@elroy.Jpl.Nasa.Gov (David Robinson) (07/12/88)
In article <27800001@ntvax>, greg@ntvax.UUCP writes: > MNP - Question > Does anyone have anything outlining the specifications for the > MNP modem protocols (Level 1-7) ? I am new to the MNP world (read VERY new) so could someone send me a small 2-3 line summary of each level and how they differ from each other? I really dont care right now about the gory details that usually comes in the "official" specs. -- David Robinson elroy!david@csvax.caltech.edu ARPA david@elroy.jpl.nasa.gov ARPA {cit-vax,ames}!elroy!david UUCP Disclaimer: No one listens to me anyway!
craig@lakesys.UUCP (07/13/88)
In article <7419@elroy.Jpl.Nasa.Gov> david@elroy.Jpl.Nasa.Gov (David Robinson) writes: > >I am new to the MNP world (read VERY new) so could someone >send me a small 2-3 line summary of each level and how they >differ from each other? > (the following is Copyright 1987, Multi-Tech Systems, Inc.) The MNP protocol is divided into several levels, or "Classes". The classes you would encounter in 1200 and 2400 bps modems are CLasses 2 through 5. When modems equipped with MNP start communicating, they will negotiate operation to the highest common MNP class between them and operate at that level. In order to alleviate some of the confusion regardig different MNP Classes, we will summarize them here: CLASS 2 This is a character (Byte) oriented protocol, where complete asynchonous characters are thransmitted along with the protocol overhead. This results in a throughput of only about 84%, which for a 2400 bps modem would yield a transmission rate of about 2000 bps. Relatively few modems were ever sold incoprorating hardware-based Class 2 MNP, although this class has been used in software-based applications. CLASS 3 This is a bit-oriented protocol, where asynchronous characters are converted to a synchronous data stream, as explained earier in this chapter. The protocl effieincy is about 108%, which yields a throughput of up to 2600 bps for a 2400 bps modem. Virtually all MNP modems sold today utilize Class 3. Both Class 2 and Class 3 are now public dimain protocls, and Class 3 has achieved "industry standard" status. CLASS 4 Class 4 is nearly identical to Class 3, except that it can yield a slightly better throughput. The Class 4 protocol is flexible in the size of the blocks that are transmitted, and by monitoring the data transmission quality, will permit larger blocks during times of lower error activity. These larger block tranmissions can increase the protocol efficiency to about 120%, for a potential throughput of about 2900 bps for a 2400 bps modem. CLASS 5 Class 5 includes the features of Classes 3 and 4, and also uses data compression techniques to increase throughput. Depending upon the type of data being transmitted, the throughput of a Class 5 MNP 2400 bos modem canbe up to 4800 bps. I have no information regarding Classes 6 or 7, sorry... -- Craig L. Stodolenak | {backbone,uunet}!marque!lakesys!craig 8307 W. Grantosa Dr. | craig@lakesys.UUCP Milwaukee, WI 53218 |------------------------------------------------------- (414) 462-8973 | "It is a moral imperitive." - 'Real Genius'