Path: utzoo!utgpu!watserv1!watmath!att!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!emory!gatech!prism!dali.gatech.edu!mikeg
From: mike@penguin.gatech.edu (Mike Gourlay)
Newsgroups: comp.sys.hp
Subject: How to test serial port?
Message-ID: <1990Nov28.111522@dali.gatech.edu>
Date: 28 Nov 90 16:15:22 GMT
Sender: news@prism.gatech.EDU
Reply-To: mike@penguin.gatech.edu (Mike Gourlay)
Organization: Georgia Tech
Lines: 49

Hiya,

	I know a way to test whether the serial port can _send_ data; 
 nohup sleep 999999999 < /dev/serial & ; stty raw 9600 < /dev/serial 
and then cat > /dev/serial, and hook up something like a dumb terminal or
a printer to see if that part works.  I have done that, and it does work.

	Now I want to test if the computer can _receive_ data okay.
How do I do it?  I figure it's a similar process.

	My serial port has failed to propperly connect to a laserjet and 
an NIU (modem like thing), and in both cases, the computer could send
data, but did not act as if it were receiving any.  In the case of the printer,
the printer's XON/XOFF was ignored, so the computer flooded the printer
with data after the printer requested that the data flow be stopped.  The 
computer even ignored the printer's dropped DTR.

	Some hardware guru help me please!!!!  Is there a hardware HP
 number I can call and yell (calmly) into?  

	Does anybody know what each of the 9 pins in a HP 9000 370
 do?  So far I've guessed:
	pin	function
	---	------
	1	chassis ground
	2	transmit data
	3	receive data
	5	clear to send
	6	data set ready
	7	signal ground

	Are these right?

	What about 4, 8, and 9?  Are there pins for DTR or RTS?

	Why is the computer ignoring a dropped DTR?  is it ignoring
a ^S (if in fact it is getting them)?  How do I test to see whether the
computer
is getting any data at all?  I know I can cat _to_ /dev/serial, but can
I cat /dev/serial?
Do I need to write a C program and open /dev/serial and read from it as
a stream?
If so, could someone test such a program before I use it and assume
that
the computer isn't working?

	Thanks, I'm desperate,
	Mike Gourlay,
	mike@penguin.gatech.edu