CS117341@YUSol.BITNET (Norman) (12/01/89)
Hello all, In the near future, I forsee myself having to decide on the purchase of several Microcom modems, most likely, along the lines of the QX/V.32c. With this in mind, does anybody out there use Microcom modems? How do you like them? Are they easy to configure? How is their technical support? Is the QX/v.32 any good? We have purchased a pair of Telebit T2500s which the people here don't seem to care for. (I found them to be good modems...) How do the Microcoms compare to Telebits? Any help would be greatly appreciated. Please reply directly to me, and I'll try to summarize (or collect & forward) to any who are interested. Oh, on a (slightly) related note, I've noticed that when connecting to non-MNP modems with MNP enabled on the T2500 results in an unusable connection. Maybe I'm mistaken, but I thought MNP was supposed to be a transparent protocol negotiated by both modems after they connect. Does anyone have any suggestions? Norman cs117341@yusol.Bitnet cs117341@sol.YorkU.CA
akcs.larry@nstar.UUCP (Larry Snyder) (12/01/89)
>With this in mind, does anybody out there use Microcom modems? >How do you like them? Are they easy to configure? How is their We have been purchasing a number of these modems using them at our customers site for dial up support. First - the modems are over priced costing as much as $1030 each (wholesale). Heck the UDS Motorola V.32/V.42b modems are being sold at retail for $1140. Second - the filtering on noisy lines is weak - causing aborted calls on a regular basis. I would assume the T2500 would be a better investment for modems being used in the Unix world - while the USR HST Dual Standard for those being used in the DOS world (both modems support V.32).
jst@cca.ucsf.edu (Joe Stong) (12/02/89)
In article <89Nov30.204838est.58891@ugw.utcs.utoronto.ca> CS117341@YUSol.BITNET (Norman) writes: >Oh, on a (slightly) related note, I've noticed that when connecting >to non-MNP modems with MNP enabled on the T2500 results in an >unusable connection. Maybe I'm mistaken, but I thought MNP was >supposed to be a transparent protocol negotiated by both modems >after they connect. Does anyone have any suggestions? It was also my understanding that MNP was supposed to have invisible negotiations. I had a certain amount of grief with an MNP modem calling a non-mnp modem, where the device attached to the non-mnp modem would print an error message and hang up if it didn't get a correctly typed password directly after connecting. What it was receiving was something like (octal) 377 375 after CD came up. I had to turn off the auto-reliable mode (MNP) to prevent this from happening. Joe Stong jst@cca.ucsf.edu
jparnas@larouch.UUCP (Jacob Parnas) (12/04/89)
In article <[25765e3f:99.1]comp.dcom.modems;1@nstar.UUCP>, akcs.larry@nstar.UUCP (Larry Snyder) writes: > >With this in mind, does anybody out there use Microcom modems? > >How do you like them? Are they easy to configure? How is their > > We have been purchasing a number of these modems using them at > our customers site for dial up support. First - the modems > are over priced costing as much as $1030 each (wholesale). Heck the > UDS Motorola V.32/V.42b modems are being sold at retail for $1140. > Second - the filtering on noisy lines is weak - causing aborted calls > on a regular basis. > > I would assume the T2500 would be a better investment for modems being > used in the Unix world - while the USR HST Dual Standard for those being > used in the DOS world (both modems support V.32). The reason that we use the Microcom's is they have the best compression currently around and you hook them up to your computer at 38400 baud. I've seen up to 33000 baud true throughput cating a file like /etc/hosts. You won't get that from a T2500. ------------------------------------------------------------------------------ | Jacob M. Parnas | DISCLAIMER: The above message is from | | IBM Thomas J. Watson Research Ctr. | me and is not from my employer. IBM | | Arpanet: jparnas@ibm.com | might completely disagree with me. | | Bitnet: jparnas@yktvmx.bitnet \---------------------------------------| | Home: ..!uunet!bywater!acheron!larouch!jparnas | Phone: (914) 945-1635 | ------------------------------------------------------------------------------
gt5302b@prism.gatech.EDU (WALKER,RICHARD S) (12/05/89)
A noisy line is easy to fix. A company called BALLco, Inc (404-979-5900) sells a telephone noise filter for $30. The one I have works fine, it's basically just a notch filter. It's well worth the price.
tanner@ki4pv.uucp (Dr. T. Andrews) (12/05/89)
In article <1989Dec4.054323.9528@larouch.uucp>, jparnas@larouch.UUCP (Jacob Parnas) writes:
) ... we use the Microcom's ... have the best compression currently
) around ... hook them up ... at 38400 baud. I've seen up to 33000
) baud true throughput cating a file like /etc/hosts. You won't get
) that from a T2500.
Quite true. From this, I believe that we can judge what the best modem
is when we wish to call up and cat /etc/hosts.
On the other hand, if we are pushing around large amounts of compressed
data (a newsfeed is a convenient example) where the modem's compression
is not effective, then you should consider a modem whose underlying
transport technology is better suited to moving bits.
--
...!{bikini.cis.ufl.edu allegra attctc bpa uunet!cdin-1}!ki4pv!tannerphilf@xymox.metaphor.com (Phil Fernandez) (12/07/89)
In article <2601@ucsfcca.ucsf.edu> jst@cca.ucsf.edu.UUCP (Joe Stong) writes: >In article <89Nov30.204838est.58891@ugw.utcs.utoronto.ca> > CS117341@YUSol.BITNET (Norman) writes: > >>Oh, on a (slightly) related note, I've noticed that when connecting >>to non-MNP modems with MNP enabled on the T2500 results in an >>unusable connection. Maybe I'm mistaken, but I thought MNP was >>supposed to be a transparent protocol negotiated by both modems >>after they connect. Does anyone have any suggestions? > >It was also my understanding that MNP was supposed to have invisible >negotiations. I had a certain amount of grief with an MNP modem calling >a non-mnp modem, where the device attached to the non-mnp modem would >print an error message and hang up if it didn't get a correctly typed >password directly after connecting. What it was receiving was something >like (octal) 377 375 after CD came up. I had to turn off the >auto-reliable mode (MNP) to prevent this from happening. From the _Telebit T2500 Reference Manual_, in the documentation for the S95 parameter (MNP Operating Mode): ... In addition, if the answer modem does not support MNP, it will receive a burst of characters from the originating modem during the first 4 seconds of the call as the originating modem attempts to make an MNP connection. Indeed, this burst of characters sent by my 2500 munges most every non-MNP modem that I ever dial. I've resorted to configuring the 2500 with S95=0 (MNP disabled) in its NVRAM. Then, I use "ATS95=2DT...." as my dialing mode when calling presumed-MNP modems. Of course, this effectively defeats the entire "Auto-reliable Mode" feature (S95=2), but c'est la vie. pmf +-----------------------------+----------------------------------------------+ | Phil Fernandez | philf@metaphor.com | | | ...!{apple|decwrl}!metaphor!philf | | Metaphor Computer Systems |"Does the body rule the mind, or does the mind| | Mountain View, CA | rule the body? I dunno..." - Morrissey | +-----------------------------+----------------------------------------------+
cag@tigger.planet.bt.co.uk (Chris Green,SSTF,5788,) (12/08/89)
From article <1989Dec4.054323.9528@larouch.uucp>, by jparnas@larouch.UUCP (Jacob Parnas): [lots deleted] > The reason that we use the Microcom's is they have the best compression > currently around and you hook them up to your computer at 38400 baud. I've > seen up to 33000 baud true throughput cating a file like /etc/hosts. You > won't get that from a T2500. > I hate to be pedantic but that's *not* 33000 baud, it's 33000 bits per second (=bps). The highest possible *baud* rate on public switched telephone lines is somewhere around 2400 baud full duplex. The reason that you can get much greater than 2400 bits per second is that a baud is a 'change of state' per second and with clever encoding each change of state transmits more than one bit of information. In addition of course compression techniques reduce the actual number of bits one has to transmit. I would be much happier if we could all use *characters* per second (or bytes maybe but that starts with 'b' unfortunately) to quote actual data transmission rates. Chris Green
rce10845@uxa.cso.uiuc.edu (Robert C Elliott) (12/10/89)
In article <1989Dec8.090429.21867@planet.bt.co.uk> cag@tigger.planet.bt.co.uk writes: >From article <1989Dec4.054323.9528@larouch.uucp>, by jparnas@larouch.UUCP (Jacob Parnas): >[lots deleted] >> The reason that we use the Microcom's is they have the best compression >> currently around and you hook them up to your computer at 38400 baud. I've >> seen up to 33000 baud true throughput cating a file like /etc/hosts. You >> won't get that from a T2500. >> >I hate to be pedantic but that's *not* 33000 baud, it's 33000 bits per >second (=bps). The highest possible *baud* rate on public switched >telephone lines is somewhere around 2400 baud full duplex. The reason >that you can get much greater than 2400 bits per second is that a baud >is a 'change of state' per second and with clever encoding each change >of state transmits more than one bit of information. In addition of >course compression techniques reduce the actual number of bits one has >to transmit. I would be much happier if we could all use *characters* >per second (or bytes maybe but that starts with 'b' unfortunately) to >quote actual data transmission rates. > >Chris Green I agree cps is the best figure to use. However, the original message can be read as technically correct. Measure your baud rate at the serial ports of the modem and computer, and you will see (in this case) up to 38400 voltage changes per second. If the original post had said the modem is talking to another modem at 38400 baud, then you can label it an error. Rob Elliott: rce10845@uxa.cso.uiuc.edu (summer: rob@embossed.com)
wiz@tabbs.UUCP (Wiz) (12/13/89)
From article <2601@ucsfcca.ucsf.edu>, by jst@cca.ucsf.edu (Joe Stong): > In article <89Nov30.204838est.58891@ugw.utcs.utoronto.ca> > CS117341@YUSol.BITNET (Norman) writes: > > It was also my understanding that MNP was supposed to have invisible > negotiations I too was under this impression, but my Octocomm OSI8224A MNP4 modem always seems to play up when connecting to non-MNP modems. Most frequently I get every character that the remote system sends preceeded with a "?". Also, I have had another problem with the MNP 4 emulation in the Octocom. When I connected to an MNP 5 modem, our throughput with an error free Z-Modem transmission was only 113 CPS, whereas if I turn off my error correcting (MNP), I get 236 CPS. Any suggestions as to what I might be doing wrong, or is MNP 4 not all that it is cracked up to be ? -- Kean Johnston ..!uunet!ddsw1!olsa99!tabbs!wiz or wiz@tabbs.UUCP "Ahhhhhh! I see you have the machine that goes PING!"
jparnas@larouch.uucp (Jacob Parnas) (12/15/89)
In article <7134@ki4pv.uucp> tanner@ki4pv.uucp (Dr. T. Andrews) writes: >In article <1989Dec4.054323.9528@larouch.uucp>, jparnas@larouch.UUCP (Jacob Parnas) writes: >) ... we use the Microcom's ... have the best compression currently >) around ... hook them up ... at 38400 baud. I've seen up to 33000 >) baud true throughput cating a file like /etc/hosts. You won't get >) that from a T2500. >Quite true. From this, I believe that we can judge what the best modem >is when we wish to call up and cat /etc/hosts. Obviously, buying a modem only for catting /etc/hosts is stupid. The reason that I noted the throughput of catting /etc/hosts was that I wanted to test the throughput of the modem in an interactive ascii environment. /etc/hosts was a large file (~140Kbytes) that I had on hand. I (and I believe many other people) like to do interactive ascii computing over a modem (from home). This includes applications that require sending data that is easily precompressed. For instance, editing files or reading news requires that data be sent without precompression, and it is very nice for it to be extremely fast. I find that if I have a large window (say 60 lines), it is much nicer if a screenful of a usenet article is sent to my screen at 33000 baud instead of 19200 baud. There are many other applications that it is nice to have compression built into the modem. For instance, SLIP. I notice a big difference between xmh performance with the Microcom's MNP 9 when compared to the Telebit T2500. Some other applications which benefit from MNP level 9 are: ftp, rcp, telnet, xrn, rdist, and 3270 emulation to VM/CMS systems. >On the other hand, if we are pushing around large amounts of compressed >data (a newsfeed is a convenient example) where the modem's compression >is not effective, then you should consider a modem whose underlying >transport technology is better suited to moving bits. I agree that MNP level 9 is not useful for sending precompressed data. I use a Telebit to get usenet and mail. But, for interactive communication of data that isn't precompressed, MNP level 9 is extremely nice. ------------------------------------------------------------------------------ | Jacob M. Parnas | DISCLAIMER: The above message is from | | IBM Thomas J. Watson Research Ctr. | me and is not from my employer. IBM | | Arpanet: jparnas@ibm.com | might completely disagree with me. | | Bitnet: jparnas@yktvmx.bitnet \---------------------------------------| | Home: ..!uunet!bywater!acheron!larouch!jparnas | Phone: (914) 945-1635 | ------------------------------------------------------------------------------
scotto@crash.cts.com (Scott O'Connell) (12/21/89)
In article <441@tabbs.UUCP> wiz@tabbs.UUCP (Wiz) writes: >From article <2601@ucsfcca.ucsf.edu>, by jst@cca.ucsf.edu (Joe Stong): >> In article <89Nov30.204838est.58891@ugw.utcs.utoronto.ca> >> CS117341@YUSol.BITNET (Norman) writes: >> >> It was also my understanding that MNP was supposed to have invisible >> negotiations > >I too was under this impression, but my Octocomm OSI8224A MNP4 modem >always seems to play up when connecting to non-MNP modems. Most frequently >I get every character that the remote system sends preceeded with a "?". > >Also, I have had another problem with the MNP 4 emulation in the Octocom. >When I connected to an MNP 5 modem, our throughput with an error free >Z-Modem transmission was only 113 CPS, whereas if I turn off my error >correcting (MNP), I get 236 CPS. > >Any suggestions as to what I might be doing wrong, or is MNP 4 not all that >it is cracked up to be ? > >-- >Kean Johnston ..!uunet!ddsw1!olsa99!tabbs!wiz or wiz@tabbs.UUCP > > "Ahhhhhh! I see you have the machine that goes PING!" How did you get stuck with an Octocom modem? I won't go into detail as to how I know this, but I'll tell you that Octocom has the attitude that "Who cares if 99% of the other manufacturers do it one way, *WE* do it right and that makes *US* better!" I'd call technical support at Octocom and ask them why you're having those problems. I'd bet their answer is either a) that's the way it's supposed to work, or, b) you need to be using our modem on both ends, or, c) check the air in your left rear spare tire and call me tomorrow. I'm hoping that Octocom has gotten better since my exposure with them, but from the looks of the problems it's the same bunch of people doing the same things. Sigh. -- Scott O'Connell UUCP: {nosc, ucsd, hplabs!hp-sdd}!crash!ipars!scotto ARPA: crash!ipars!scotto@nosc.mil INET: scotto@ipars.cts.com