Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!lll-winken!gauss.llnl.gov!casey From: casey@gauss.llnl.gov (Casey Leedom) Newsgroups: comp.dcom.modems Subject: Re: Telebit T2500 - are they a good deal? Keywords: telebit T2500 Message-ID: <69198@lll-winken.LLNL.GOV> Date: 4 Oct 90 01:26:56 GMT References: <14829@cbmvax.commodore.com> Sender: usenet@lll-winken.LLNL.GOV Reply-To: casey@gauss.llnl.gov (Casey Leedom) Organization: Lawrence Livermore National Laboratory Lines: 39 / From: grr@cbmvax.commodore.com (George Robbins) | | BTW, looking at your addendum, did they add support for a 38.4 KBPS interface | rate? If not, then it's going to be real hard to get a 4X performance boost \ at 9600 BPS, eh? / From: mju@mudos.ann-arbor.mi.us (Marc Unangst) | | I think V.42 and V.42bis are only useful at 1200bps and 2400bps (V.22, | Bell 212A, and V.22bis), although they may also work at 9600bps | (V.32). The addendum doesn't say anything about talking to the modem | at 38.4Kbps, and since the manual doesn't say either, I'd guess that \ 19.2Kbps is still as high as you can go. It works quite nicely in V.32/V.42bis mode. I use it all the time. However, I'm now getting nearly 19,200 full blast. There are times when I definitely think I'm limited by the 19.2Kbps top interface rate on the T2500. I don't think it's a big problem yet because the 4x throughput rate for V.42bis is a maximum and I would bet that it's averaging about 2x. But, when V.32bis is brought out with a base rate of 14.4Kbps, a V.42bis maximum rate of 57.6Kbps and an expected average of maybe 28.8Kbps, 19.2Kbps is going to be totally inadequate. I brought this issue up with an engineer from Telebit. I asked him if they were thinking about adding a 38.4Kbps interface speed setting to the T2500. He said yes, they were thinking about it but didn't know if the T2500 had the CPU horse power to handle that kind of rate. He pointed out that the T2500 was really just their old platform with a V.32 engine tacked on top. Oh well. Nothing is forever. I presume that Telebit will offer T2500 owners an upgrade path if new hardware is required. They've been very good about that in the past. It is somewhat disappointing because when Telebit brought out the T2500 they claimed that the old design wasn't fast enough to handle V.32 and thus the T2500 design would incorporate enough CPU to handle the current and near future needs. Or maybe I was just reading between the lines. Casey