Zmodem with T2500/uucp settings (was re:DSZ ZMODEM problem)

[Greg Andrews]

In article <1991Mar18.151002.1423 at crom2.uucp> jim at crom2.uucp (James P. H. Fuller) writes:
>In <1991Mar16.190010.21805 at cs.wayne.edu> lee at pandora.cs.wayne.edu (Harrison Y. Lee) writes:
>
>>	Does anyone knows how to use DSZ Zmodem protocol in unix?
>>            [description deleted]
>
>    I'd like to hear about this also.  I have Forsberg's rz and sz compiled
>for ISC Unix rel.2.2  (SysVr3.2) and whenever people call from DOS machines
>and try to download stuff using dsz they get lots of timeouts and error re-
>covery and a very low transfer rate.  My modem is a T2500 with the registers
>optimized (as best I can) for unix/uucp.
>   [stuff deleted]
>Would a newer rz/sz help, or is it my modem settings or something else?
> 

The modem settings might be a factor if you have S111=30 permanently set
in your modem, and you're seeing these problems in PEP mode.

While the modem has protocol spoofing active, it's watching for evidence
of that protocol in the data stream.  If the modem sees that protocol
starting up, it jumps in and starts getting involved in the transfer.

Sometimes, the modem can be fooled by the data stream.  It thinks it
should get involved in the transfer, when in reality a different protocol
is being used.  I haven't seen this happen when Zmodem is transferring
while the modem is watching for uucp, but the possibility is there.

If you're seeing this problem in your PEP connections, then you may want
to set your modem's S111=0 and try it again.  If this works, then you
probably want to use S111=255 in your modem and have your Telebit callers
set their modem's S111=30 when they call for uucp, and S111=0 or 255 when
they call for Zmodem.

If the problem happens when people call from non-Telebit modems, then
disregard all of the above -- protocol spoofing wouldn't be a factor
if the other modem doesn't enable it with your modem.


-- 
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|  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
|                 |   Internet: gandrews at netcom.COM                      |
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