[comp.dcom.modems] Penril Alliance V32 and Zoom Modem problem

lrogers@oasys.dt.navy.mil (Larry Rogers) (02/19/91)

We have a bank of Penril modems that are having a difficult time connecting
with a remote Zoom modem (unknown version).  Our Penril's are able to connect t
to other modems without problems, including the ability to "step down" to 2400
or 1200.  The Zoom modem are set to receive at 2400.  I was told that this
modem is able to connect to many other types of modems, so I think it may be
particular to this combination of modems.  
Our bank of modems is the next release after revision D. No manual.
We tried an earlier release of the Penrils, revision D, and it was able to
connect to the Zoom after several lines of garbage were recieved.  The bank of
modems display several errors being recieved and then time-out, disconnect, or
whatever after 20 seconds.  The basic configuration for the bank of Penrils
seem to be a default, however, this could be wrong.

The bank of Penrils need to dial out to many other sites.  A least common
denominator problem is rapidly evolving, it seems.

Could someone tell me:

a) Does the reciving modem initiate the discussion of what protocols are to be
used?

b) Are there any known problems with these two modems talking to each other?

c) Are there any Penril paramters i should try changing to accomodate this
problem?  

tnixon@hayes.uucp (02/20/91)

In article <5975@oasys.dt.navy.mil>, lrogers@oasys.dt.navy.mil
(Larry Rogers) writes: 

> a) Does the reciving modem initiate the discussion of what protocols are to be
> used?

The answering modem always transmits first, and the calling modem 
listens.  I don't know whether or not the Alliance V.32 uses the 
CCITT Automode procedure, but if it does, it interworks with V.22bis 
modems by first sending an answer tone (with phase reversals in it, 
in case the calling modem is V.32), the follows this by three 
seconds of the Unscrambled Binary 1 signal (2250Hz plus 2850Hz 
together) that a V.22bis modem expects to see.  Perhaps the Zoom 
needs more than three seconds, or perhaps it is confused by the 
phase reversals in the answer tone.  Hard to say.

> b) Are there any known problems with these two modems talking to each other?
> 
> c) Are there any Penril paramters i should try changing to accomodate this
> problem?  

If I were in your situation, I would call Penril Technical Support 
and ask these questions.  It's possible that Penril has a parameter, 
as do Hayes modems, to extend the USB1 transmission time from 3 
seconds to a larger value, in case your Zoom modems need more time 
(but they shouldn't; the standard says they should respond after 
only about 600 msec of USB1).  Unfortunately, Zoom is not known for 
quality.

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net

sichermn@beach.csulb.edu (Jeff Sicherman) (02/21/91)

In article <3789.27c251f8@hayes.uucp> tnixon@hayes.uucp writes:


   [ deleted specifics of Penril problem ]

> ......  Unfortunately, Zoom is not known for 
>quality.

>Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
>Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
>P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
>Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net

  Is this a gratuitous slap at a competitor or can you cite specifics about
this, recognizing you do have an inherent bias.

  I have been using Zoom products for rather low end modem use and am 
considering some of their new products for higher-end demands (v42bis)
I have noted the new stuff has a 2 year warranty compared to a 7 y\on the more
garden variety ones and would like to truly know if there is a reason
for suspicion.

Jeff Sicherman

tnixon@hayes.uucp (02/22/91)

In article <1991Feb21.062918.2304@beach.csulb.edu>,
sichermn@beach.csulb.edu (Jeff Sicherman) writes: 

> In article <3789.27c251f8@hayes.uucp> tnixon@hayes.uucp writes:
> 
>> ......  Unfortunately, Zoom is not known for 
>>quality.
> 
>   Is this a gratuitous slap at a competitor or can you cite specifics about
> this, recognizing you do have an inherent bias.

Yes, it is a gratuitous slap at a competitor, which I probably 
shouldn't do even if it is true.  I don't know about Zoom products
from personal experience, but base my comments on many, many reports 
that I've seen on CompuServe of recurring problems with Zoom modems.
It's sort of "conventional wisdom" on IBMCOM Forum to avoid Zoom
products. Sorry; I should have qualified the source of the comment
when I initially made it. 

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net

kgallagh@digi.lonestar.org (Kevin Gallagher) (02/23/91)

In article <3789.27c251f8@hayes.uucp> tnixon@hayes.uucp writes:
>[stuff deleted]
>If I were in your situation, I would call Penril Technical Support 
>and ask these questions.  It's possible that Penril has a parameter, 
>as do Hayes modems, to extend the USB1 transmission time from 3 
>seconds to a larger value, in case your Zoom modems need more time 
>(but they shouldn't; the standard says they should respond after 
>only about 600 msec of USB1).  Unfortunately, Zoom is not known for 
>quality.
You don't say if this observation about Zoom modem quality is from
personal experience or from hearsay.

I purchased a Zoom modem several years ago, the model PC 2400 XL.  It was
their super delux internal modem, which they later discontinued.  It is fully
Hayes compatible with lots of additional features.  Very early on I
experienced a problem uploading at 2400 baud.  Unfortunately, the problem did
not consistently manifest itself.  Zoom's hot line provided me with a list of
things to try before deciding to ship it back to them for service.  After
trying them all, they failed to help.  So I sent it in for service.  Zoom kept
it for a week and were unable to reproduce the problem.  But while they had
it, they went and upgraded the ROM chip to the most recent version
free-of-charge.

Well, I still had the 2400 baud upload problem, so the technican speculated
that a particular chip might have an intermittent problem.  To minimize my
loss of use time, he asked if I could, or knew someone who could, replace
the chip on the modem.  I did, so rather then having to ship it back, they
shipped me the chip.  I was impressed.  Unfortunately, the new chip did not
fix the problem.  So I sent the modem back a second time.  Seven days later, a
brand new modem arrived, shipped next day air.  I have been happy ever since!

I cannot, however, speak to the quality of the new line of inexpensive Zoom
modems that have appeared in the past year.  I can only attest that after
getting the replacement modem, I have been pleased with its reliability.  I
do know that the new line of inexpensive Zoom modems comes with a 7-year
warranty.  This suggests to me that Zoom must have some degree of confidence
in the quality of its product.  How long is the warranty on Hayes modems?

-- 
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DSC Communications Corporation   Addr: MS 152, 1000 Coit Rd, Plano, TX 75075
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