From: jamesp@iagu.itd.adelaide.edu.au (James Pickering)
Newsgroups: aus.comms
Subject: Re: A reliable 9600 modem
Keywords: Modem, 9600baud
Date: 24 Aug 92 01:30:24 GMT
Organization: University of Adelaide, South Australia

In article <8280@sirius.ucs.adelaide.edu.au> simon@ucs.adelaide.edu.au (Simon Hackett) writes:
>eeltw@marlin.jcu.edu.au (Lloyd T Walker) writes:
>
>>      I'm involved in trying to set up an info service for disabled
>>people and interested people here in Townsville and will ba making it
>>accessable by modem.  I've noticed in this group some comments re
>>Netcomm vs Maestro etc.  Has anyone some good recommendations for a
>>reliable 9600baud modem (so we don't limit the system to 2400).

As much as people flame the Netcomms, they do work very well if they're
only going to be used at 9600 and lower speeds, and you don't
lock the terminal rate to anything other than the connected rate.
If you go above 9600, you typically lock the port baud rate at 19.2K
which causes serious handshaking problems with sending continuous data
through the modem at high speeds esp with compression (ie it hangs up
immediately). I've had these problems with M5's and E7's, and nobody
has yet given me a solution.

>I run a network link over a pair of Dataplex DPX-496 modems at 14,400 bps
>(V.32bis). These modems also run all the lower speeds and support
>V.42bin and MNP 4 & 5 compression.

You say they do V.42bis - do they do V.42 as well? Modems go much faster
with V42bis if they have V.42.

>Technically I think they're very similar
>to the Scitec modems that David Bennett notes in a previous posting. I have
>had very good experiences with these modems, they hold onto circuits very
>well indeed, and will talk to practically anything (except for
>those darn Netcomm 9600 modems that won't talk to anything except another
>of themselves, argh).

Extend that to "anything except another Rockwell" - if you don't have
them set up right they don't talk to other modems except Rockwells. I've
managed to get them connecting from 300 to 9600 fine to everything, it's
just as soon as you go above 9600/MNP4 they have problems.
With another 12K Rockwell they're brilliant if you can't afford a V.32bis
modem.

>I recommend them for consideration, they cost around
>the same as the Scitec's and probably are technically pretty similar.

How much do they cost? The new Netcomm V.32bis V.42bis (not V.42) are
around $11,000 (or $750/$650 sysop deal on M7F/E7).

>Both
>modems use decent technology to do the V32bis (I'm not sure whether
>the DPX-496's are DSP or modem-chipset based, but whatever they use,
>it's pretty good).

If they don't like Netcomms I'll bet they're not Rockwell based.

>One nice feature the Scitec's have that the DPX doesn't, that I think is cute -
>the Scitec can be told to display the serial port handshake/carrier lines
>on the front panel LCD, and can display these for both the local *and* remote
>modems - i.e. you can quite nicely run the remote modem via the local modem's
>front panel - cute.

The SupraFax 14.4 can do the local end on its LCD - not sure if they can
do the remote end though (but the Supras aren't AUSTEL approved -
shame really because they're a very nice modem at a nice price).

>I'd be very happy to recommend either the Dataplex DPX-496's or
>the Scitec 14.4K's. Either way, you might as well get the ones that
>can go to 14.4K, they don't cost enough more than the 9600's do to be
>worth *not* getting them. Half as fast again...

Or perhaps wait a month longer until the ZyXel modems get V.32.bis.b
16.8K working (then around 6 months until anyone can get a reasonable
ROM for the chipset 8-)



-- 
+---------------------------------------------------------------------+
| James Pickering, University of Adelaide, South Australia            |
| Disclaimer: This is my opinion, not those of the above organisation |
| E-Mail: jamesp@iagu.itd.adelaide.edu.au jdpicker@cs.adelaide.edu.au |
Newsgroups: aus.comms