re courier vs sportster note followups to comp dcom modems for obvious reasons in article r mb h usenet ins cwru edu da cleveland freenet edu andy nicola writes in a previous article cs sd ae maccs mcmaster ca holly ks says what is the difference between the us robotics courier v bis external and the sportster external i see that the price of a sportster has dramatically dropped to below but the price of the courier remains above anyone with knowledge of both of these modems or anyone that owns a courier the courier is their top of the line product thus the higher price i ve never taken a real look at the sportster line only couriers but from what i ve gathered it s basically more of an entry level modem probably doesn t meet the same specifications that the courier does i m not sure if the sportster line is fully dsp driven like the more recent courier modems are so upgrades in the future may be an issue again take all of the above with a grain of salt i ve never evaluated the sportster so i m going by bits and pieces that i ve heard if you want a real answer post the question in comp dcom modems and you ll find people who have worked with the sportster personally though if i were going to look at the courier modems i d buy the dual standard then i d get both hst and v bis in fact this is exactly what i did i m sitting here looking at my usr ds right now and now to correct a few very incorrect statements folks if you want to get reliable answers to modem and or uart questions post them to comp dcom modems if you post in other groups you never know what you ll get in the way of an answer you may very well get a good answer or you may get something like the one below at least in cdm if someone posts complete and utter bs you ll see a flurry of folks correcting them to avoid spreading faulty info the sportster at has v error control and v bis data compression just as it does at lower speeds too there is absolutely nothing in either ccitt recommendation v or v bis that says that they can only operate on modems that are running v bis v bis of course is currently only standardized for operation on top of v in its primary mode of operation lapm but that s about as far as that goes and just in case there s some confusion on this v v bis are also supported by the courier line unless you have a really ancient one the difference with the courier is that it can run at and only in the hst mode take a second look at the original question in a previous article cs sd ae maccs mcmaster ca holly ks says what is the difference between the us robotics courier v bis external see the v bis up there the question was not about the courier hst modem or about the courier dual standard it was about the courier v bis modem the modem in question does not support hst period it therefore does not support the kb hst also not all courier hst courier dual standard modems support the kb version of hst my dual standard only supports hst at kb there are even older models that only run hst at kb this is a proprietary mode of usr and it will only connect to another of the same type unit to achieve this speed hst is usr s proprietary modulation scheme but we re not talking about hst we re talking about v bis v bis is most definitely not a proprietary modulation scheme the sportster will do asynchronous transmissions as well as synchronous the hst is one way only i do hope you didn t mean for these two sentences to be related in some way first off v and v bis are both synchronous and asynchronous this is part of the ccitt recommendation i e part of the standard it isn t a feature unique to the sportster i just looked at the appropriate chapter in the courier ds manual second hst is not one way only more correctly put it is an asymmetrical modulation scheme meaning it doesn t work at the same speed in both directions hst operates at in one direction and has a low speed back channel in the other direction the high speed channel goes in the direction of the higher data flow this is fine if you re logged on to say a bbs and type one letter and get screens of info back transfer files not using bimodem etc there is of course a penalty for turnaround time when the high speed channel needs to reverse directions v and v bis are both symmetrical meaning they do transfer the full data rate in both directions at the same time third synchronous vs asynchronous has absolutely nothing to do with symmetrical vs asymmetrical they are two completely different topics the hst s will be upgradeable to the v fast spec when it is available again more correctly put some of the courier line will be upgradeable to whatever v fast is called when it s complete if you have the large footprint courier modems like i do you re s o l there was an upgrade plan a while back to upgrade to a small footprint variety which could eventually be upgraded to support v fast but the cost of the two upgrades together pretty much put it higher than just buying a new modem later jim 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