kimcm@olamb.UUCP (Kim Chr. Madsen) (11/11/86)
In article <2942@cbosgd.ATT.COM>, mark@cbosgd.ATT.COM (Mark Horton) writes: > I haven't followed it closely, but yesterday a salesperson pointed > at a TeleByte modem, said the cost was $3500 each, and that it did > 19.2K over regular dialup lines. Part of this is probably done with > data compression, so it may not help your application. Well, at our offices we use a DOV-Modem (Data Over Voice) which is able to talk between our two UNIX boxes at 0-19200 Baud (Asyncronous) or (600,1200, 2400,4800,9600,19200 Baud Syncronous) The DOV modem is a special modem, which uses a intenal telephone-net so that the lines can be used in conversation and datatransmission at the same line. This is done by dedicate the low frequency area to voice and the high frequency area to datacommunication. I don't know who distributes the modems but they're manufactured by the company "Datentechnik" in Austria and the price (in Denmark converted to US$) is about $400 each plus a philter to $50 <Kim Chr. Madsen>
ron@brl-sem.ARPA (Ron Natalie <ron>) (11/11/86)
In article <2942@cbosgd.ATT.COM>, mark@cbosgd.ATT.COM (Mark Horton) writes: > I haven't followed it closely, but yesterday a salesperson pointed > at a TeleByte modem, said the cost was $3500 each, and that it did > 19.2K over regular dialup lines. Part of this is probably done with > data compression, so it may not help your application. Once again, as pointed out before, some of these cheap and slick data compressed/error corrected modems are pretty atrocious. The Telebyte for instance is damn near unusuable for either normal UNIX use or UUCP as it is really half duplex and takes forever to turn the line around. -Ron
caf@omen.UUCP (Chuck Forsberg WA7KGX) (11/14/86)
In article <464@brl-sem.ARPA> ron@brl-sem.ARPA (Ron Natalie <ron>) writes: :In article <2942@cbosgd.ATT.COM>, mark@cbosgd.ATT.COM (Mark Horton) writes: :> I haven't followed it closely, but yesterday a salesperson pointed :> at a TeleByte modem, said the cost was $3500 each, and that it did :> 19.2K over regular dialup lines. Part of this is probably done with :> data compression, so it may not help your application. : :Once again, as pointed out before, some of these cheap and slick data :compressed/error corrected modems are pretty atrocious. The Telebyte :for instance is damn near unusuable for either normal UNIX use or UUCP :as it is really half duplex and takes forever to turn the line around. Unusable with unsuitable protocols, but not unusable! DCA recently tested Pro-YAM's public domain ZMODEM protocol with a pair of their TrailBlazer modems, and obtained a throughput of about 14,000 bps (a record, comfortably surpassing "Crosstalk-FAST"). ZMODEM, it happens, is ideal for these modems because the receiver does not have to acknowledge every transmitted block, only to send error packets when necessary. Of course, even ZMODEM will be slowed if one must send many itty bitty short files, but this is not the usual case. For more information, look at the ZMODEM protocol description sent over net.sources some time ago, available in ZMODEM.ARC on Telegodzilla. Chuck Forsberg WA7KGX Author of Pro-YAM communications Tools for PCDOS and Unix ...!tektronix!reed!omen!caf Omen Technology Inc "The High Reliability Software" Voice: 503-621-3406 17505-V Northwest Sauvie Island Road Portland OR 97231 TeleGodzilla BBS: 621-3746 2400/1200 CIS:70007,2304 Genie:CAF Source:TCE022 omen Any ACU 1200 1-503-621-3746 se:--se: link ord: Giznoid in:--in: uucp omen!/usr/spool/uucppublic/FILES lists all uucp-able files, updated hourly
phil@amdcad.UUCP (Phil Ngai) (11/15/86)
In article <129@olamb.UUCP> kimcm@olamb.UUCP (Kim Chr. Madsen) writes: >In article <2942@cbosgd.ATT.COM>, mark@cbosgd.ATT.COM (Mark Horton) writes: >> I haven't followed it closely, but yesterday a salesperson pointed >> at a TeleByte modem, said the cost was $3500 each, and that it did >> 19.2K over regular dialup lines. Part of this is probably done with >> data compression, so it may not help your application. > >Well, at our offices we use a DOV-Modem (Data Over Voice) which is able to >talk between our two UNIX boxes at 0-19200 Baud (Asyncronous) or (600,1200, >2400,4800,9600,19200 Baud Syncronous) Let's talk apples and oranges here. DOV only works if you have a metallic path. When Mark Horton says dialup lines, he's talking about a communications path with bandwidth between (roughly) 300 to 3000 Hz. The methods used to communicate over a few hundred feet are quite different from the ones used to communicate across the world. I would have to add that I don't like Telebyte style modems either. I would rather have a real modem, like the V.32 style. -- The VT220 keyboard is an <iS<o standard. That means the French can hate it as well as the Americans. <phil <ngai +1 408 749 5720 <u<uC<p: <[ucbvax,decwrl,ihnp4,allegra<]!amdcad!phil AR<pA<; amdcad!phil@decwrl.dec.com