Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!hplabs!hpda!hpcuhb!hpindda!kmont
From: kmont@hpindda.HP.COM (Kevin Montgomery)
Newsgroups: comp.sys.hp
Subject: Re: Serial Port ?
Message-ID: <4310015@hpindda.HP.COM>
Date: 18 Oct 88 19:38:28 GMT
References: <1135@helios.ee.lbl.gov>
Organization: HP Information Networks, Cupertino, CA
Lines: 46

/ hpindda:comp.sys.hp / super@ux1.lbl.gov (Michael Helm) /  6:55 pm  Oct 14, 1988 /
> I decided to do something useful with the RS-232-type port
> on an HP-9000/3xx, & attach an old 2623a terminal to it.  
> Unfortunately...I can't quite get it to go.  I can cat files
> to the terminal, & sometimes a login: prompt is issued,
> but I can't login or proceed any further.

I don't work down in the datacomm labs, but I'll take a stab
and suggest:

1) try a loopback (ie. jumper pins 2 & 3) on the terminal end 
   of your cable, then use 'tip' or 'cu' with the hardwire option
   (you may have to tweak /etc/remote to look at the right tty in 
   /dev) to go out that port.  If everything is okay in the 9000
   setup and the cable, then everything you do should be echoed
   back, and your problem was in the 2623a (or you needed a "null 
   modem" cable (pins 2 & 3 switched in the cable on the terminal end).

2) If this didn't work, then it's either your cable, or the 9000.
   try looping back at the 9000 rs232 port.  If 'cu' works there,
   then the problem was in the cable.  If it didn't, then it's a
   problem with the 9000.

3) If it's a problem with the 9000, then it's either a problem 
   with how you were invoking 'cu' or 'tip', or it was an actual 
   problem with how the tty was setup.  Try using 'cu' out an
   already working port and see if it works.  If so, then you were
   probably using 'cu' correctly, and the problem was in configuring
   the new tty. 

4) If the problem was in configuring the tty, then look at the 
   MAKEDEV script (I think these still exist, are called this, and
   are still distributed with HP-UX) to see what the differences
   are between how you had set up the new tty, and how the other 
   ttys are set up.  If you still can't find any problem, call 
   your friendly, neighborhood HP representative- they live for
   tracking down such things...


				Hope it helped,
				  kevin

ps: off hand, since you say that you can send to the terminal (by
    using /bin/cat and by starting up a getty on it), and that you
    can not send anything back, I'd say that it's probably a problem
    in the cable (1st choice), or in the terminal config.