Date: Tue, 15 Jan 2002 00:27:34 +0100 From: Nils Holland <nils@tisys.org> To: Joe & Fhe Barbish <barbish@a1poweruser.com> Cc: Bob Hall <rjhalljr@starpower.net>, FBSD Questions <questions@FreeBSD.ORG> Subject: Re: Zoom modem, how do I use it? Message-ID: <20020115002734.A7597@tisys.org> In-Reply-To: <LPBBIGIAAKKEOEJOLEGOEEIICMAA.barbish@a1poweruser.com>; from barbish@a1poweruser.com on Mon, Jan 14, 2002 at 05:15:47PM -0500 References: <20020114165544.A552@starpower.net> <LPBBIGIAAKKEOEJOLEGOEEIICMAA.barbish@a1poweruser.com>
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On Mon, Jan 14, 2002 at 05:15:47PM -0500, Joe & Fhe Barbish stood up and spoke: > I just exchanged a zoom external modem V.92 for a V.90 model. > V.92 is a brand new dial protocol which most ISP are in no > hurry to support. > I do not think FBSD sio can handle it. V92 is actually nothing that's much different, nor useful. As with V90, downstream speed is limited to 56k. Upstream speed is increased from (I think) 33.6k to (I think) 48k. Now this is probably not something too great. Another thing is that at the same time V92 got introduced, a new compression method called (once again, I think) V44 is also intoduced. This new method is supposed to be more effective than the current compression used (V42), but tests actually demonstrated that the increase in performance is almost not noticable. Download 3 MB of text and you may see something, download a 3 MB .tar.gz file and you won't. And then, V92 is supposed to be able to put the Internet connection "on hold" so that you can use the phone and then contine with your net connection where you left of. Basically, current modems can do the same: Just hang up and redial. The last new thing in V92 is that the connection can be established faster, as the handshake procedure now only takes about 12 seconds instead of commonly 25 seconds. This works by the modem storing the line conditions it encountered during the last connection, so that a subsequent connection to the same destination can be made by "skipping" some of the tests that determine the line quality. Now, the above is the reason why neither ISPs, nor end users have yet rushed out to get V92. Basically, I don't think this very minimal increase in performance is worth it. However, besides the above facts, V92 doesn't neccessarily mean and "visible" changes to the modem. V92 modems don't put any more demand on the sio driver. Neither do they need some "new" commands to work (except to use this "connection on-hold" feature and the new compression). Of course, some manufacturers may have done strange things to their V92 modems so that they don't work properly, but I can tell you that a V92 modem from US Robotics works just fine under FreeBSD (although I could not test the V92 capabilities, as my ISP doesn't support that standard). Generally, *if* the V92 modem works with standard AT commands (and USR modems do), it should work fine under FreeBSD. One more note: V92 and the new compression standard V44 are not really related. Some websites will tell you that V44 is a part of the V92 specs, but that is not really true. Some manufacturers sell V92 modems with the (old) V42 compression, but they don't mention that fact. Other manufacturers do implement V44 along with V92 in their new modems. If that's true for a given modem is hard to find out, since it seems that many manufacturers don't want to tell you that they use V42 while their competitor offers V44. I hope these information were mostly correct. They should be, but I didn't have the time to verify them. You may want to try http://www.v92.com for more. Greetings Nils -- Nils Holland Ti Systems - FreeBSD in Tiddische, Germany http://www.tisys.org * nils@tisys.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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