Xref: utzoo comp.unix.sysv386:9240 comp.dcom.modems:10541 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!uunet!europa.asd.contel.com!wlbr!lonex.radc.af.mil!blackbird.afit.af.mil!udecc.engr.udayton.edu!tut.cis.ohio-state.edu!VAX1.CC.UAKRON.EDU!neoucom.edu!wtm From: wtm@uhura.neoucom.EDU (Bill Mayhew) Newsgroups: comp.unix.sysv386,comp.dcom.modems Subject: Re: Getty for ISC/Telebit T-2500 w/autobaud via the CONNECT msg? Summary: Really about inexpensive v.32 modems Keywords: Telebit, getty, autobaud, bi-directional Message-ID: <1991Jun21.045712.26615@uhura.neoucom.EDU> Date: 21 Jun 91 04:57:12 GMT References: <1991Jun15.030807.28565@pegasus.com> <1991Jun15.154304.25987@uunet.uu.net> <1991Jun19.213521.21982@digibd.com> Organization: Northeastern Ohio Universities College of Medicine Lines: 48 A rather inexpensive, if not the least expensive, v.32 modem of credible qualtiy is made by GVC. I purchased mine in single quanity for $405. Price for ten or more is $395. GVC is based on the ubiquitous Rockwell v.32 chipset engine and includes MNP level and v.42 / v.42bis lap-m error correction and compression provided by a Z-80 running Softart's MNP/v.42 firmware. The command processor is an 8031 with 32K of its own firmware. The maximum interface speed is 38400, so you can get full benefit of v.42bis on a clean link. The manual is relatively well written, but the v.42 commands are covered in a supplement that could be misplaced. Fortunately, AT&H is an on-line manual that lists all of the many commands. There is EEPROM (not battery backed CMOS!) that can store two configurations; the contents may be viewed with AT&V. GVC was rated #2 in the PC Week v.32 modem poll just behind Digicomm. I don't currently have a line impairment test set, but subjectively GVC performs on par with Digicomm and Hayes for noise rejection and sensitivity. I have a trunk circuit that I can dial up that has a sync slip problem that renders non MNP 1200 baud and 2400 modems unusable. I was able to hold a connection between the GVC and Digicomm on that line at 9600 with the test light on the GVC blinking regularly (confirming the sync slip) showing the error correction. Thoughput was better than 800 char / sec. I work in a computer support center and have a chance to tear apart the GVC modem and scrutiize it. It is very well made from decent materials. I do not recommend the internal GVC 9600 (for IBM ISA bus) for Unix users becuase the UART is only an 80C450. This means that you can't take advantage of interrupt overhead reduction by employing the fas 2.08 driver and Nat. Semi. 16550 Uart chip. The 80C450 on the GVC internal modem is a surface mount 40 pin chip which makes its replacement with 16550 rather impractical. To stay non-commercial, anybody that wants to know the vendor should contact me via email. I have no connection with GVC other than as a user (who is now $405 less rich than before!) PS: speaking of Digicomm, they now have a new firmware release that supports v.42 lap-m, but not v.42bis. The upgrade is free from Digicomm technical support (ask for Dave). Bill -- Bill Mayhew NEOUCOM Computer Services Department Rootstown, OH 44272-9995 USA phone: 216-325-2511 wtm@uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm via internet: (140.220.001.001)