Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucsd!ucbvax!Z.NSF.GOV!mmorse
From: mmorse@Z.NSF.GOV ("Michael H. Morse")
Newsgroups: comp.protocols.tcp-ip
Subject: Problem with Xmodem and 3Com terminal server
Message-ID: <9010312149.AA07742@z.nsf.gov>
Date: 31 Oct 90 21:49:18 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 32

I am having a problem getting Xmodem to work between a Sun workstation
and a PC running a terminal emulator.

The PC uses a modem and a dial-up line to communicate, but it cannot
get to the workstation directly because the workstation has no serial
ports.  Instead, the PC logs on to some other host, and then uses
telnet to get to the workstation.

We have a 3Com terminal server that is normally used in this situation,
but we've found that Xmodem does not work (the PC nacks everything it
gets) in this configuration.  However, if the PC logs onto one of our
Ultrix hosts, and in effect uses it for a terminal server to telnet to
the workstation, Xmodem works fine.  Subsequent tests have absolved the
terminal emulator (on the PC) and the xmodem program on the
workstation, leaving suspicion around the telnet implementation
on the terminal server.

I suspect this has something to do with parity, since the ASCII
characters transmitted by Xmodem, and received by the PC are
identical.  Has anybody run into a similar problem? Any information on
how telnet reacts when raw mode is selected would be appreciated.

Thanks in advance.

--Mike

-- 

Michael Morse                           Internet: mmorse@note.nsf.gov
National Science Foundation               BITNET: mmorse@NSF
                                       Telephone: (202) 357-7659
                                             FAX: (202) 357-7663