AIX 3 looses serial ports

[Robin D. Wilson]

In article <1489 at msa3b.UUCP> kevin at msa3b.UUCP (Kevin P. Kleinfelter) writes:
)YAASPP - Yet Another Aix Serial Port Problem
)
)Our 6000 "looses" serial ports. We have 32 modems on the 64 port adapter.
)Once the system decides there is a problem with a port, it will write to
)it, but reads always act as if there is no data incoming.
)For example, if we enable a port with a "smart" modem in echo mode,
)AIX sends "login:" and the modem echos "login:" and AIX sends
)"password:" and the modem echos "password" ad nauseum.  AIX cleverly
)assumes that there is a problem with the port, and apparently marks it
)as faulty.  From that point forward, all input from the port is
)ignored.  The only fix I have found is to reboot.

Well,... There are really 2 problems here: 1) getty will not say "login:" 
unless it detects carrier on the tty.  If there is a carrier signal present
then the modem SHOULD be connected, OR the modem has carrier strapped high.
DON'T STRAP CARRIER HIGH ON THE MODEM!!!!!  2) If the port is marked "BAD" 
by AIX, it is because you were generating bad logins OR there were too many 
tty overruns (interupts).  If you turn off the modem, and then disable the
port, this should allow the port to be cleared.  As long as AIX sees CD, 
DSR, RTS/CTS, etc. coming from the device on the tty, it will leave it marked
BAD.

)Deleting and recreating the /dev/tty? does not fix the problem.

You will still need to remove the offending signals, this is a "feature".


-- 
+-----------------------------------------------------------------------------+
|The views expressed herein, are the sole responsibility of the typist at hand|
+-----------------------------------------------------------------------------+
|UUCP:     robin%aixserv at uunet.uu.net                                         |
|USNail:   701 Canyon Bend Dr.                                                |
|          Pflugerville, TX  78660                                            |
|          Home: (512)251-6889      Work: (512)823-3015                       |
+-----------------------------------------------------------------------------+