ITEM: D5785L

128 port, I want to set up printer


See absttract.


   The customer is having trouble setting up an Epson FX 1050 printer.
He wants to attach it via the 128-port adapter.  He attempted to define the
device as a 'printer' device (as opposed to a 'tty' device). However, he
could not even 'cat' to the device using the 'cat /etc/passwd > /dev/lp1'.
He would get an error that said:

ksh:lp1:cannot create

He said that they had previously attached a 3151 terminal to the port and
it worked successfully.

First, I had the customer check the printer device stack by typing the
following command:

     /usr/lbin/tty/stty-cxma get lp1

The output looked like this:

     cxma, dtr, dtropen, xon, sptr

The sptr indicates that the sptr ("serial printer line discipline") was
correctly loaded at boot time.  If not, 'posix' (tty or terminal discipline)
would have appeared instead of the sptr.  However, 'dtr' indicates that
the device was configured with the DTR communication protocol 'on'.  For
the 128-port adapter, it should be off.  In the SMIT configuration of the
device this parameter can be changed (the default is 'yes').  After
changing this parameter, the printer still did not work at all.


The printer is not raising RTS, which is a key reason the printer won't work
when defined as a printer.  AIX expects CTS to be high (raised by RTS on the
printer).  When defined as a tty, AIX doesn't expect CTS to be high.

Recommended that they jumper pins 20 to 4 on the printer side to raise CTS 
on the system side.

Also, there is a fix for DTR handshaking when altpin is set.  With 3.2.4 if 
you use DTR handshaking and have set altpin, the system will immediately turn
off flow to the port (it sees DTR as dropped).  So we ordered a fix for 
APAR ix36881.

Support Line: 128 port, I want to set up printer ITEM: D5785L
Dated: October 1993 Category: N/A
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