Plotter attached to Xstation will not plot at 38400 baud

4.1.4, model 390, Xstation 120, Cal-Comp serial ploter attached to the

Customer cannot print to the plotter attached to the Xstation 120
at baud rate speeds greater than 9600. The customer has another
Cal-Comp serial ploter attached directly to the RISC and it can
print higher than 9600 bps.

I asked the customer to walk me thru his plotter setup. It was....

smitty spooler
Add a Print Queue
xstation                Printer Attached to Xstation
Xstation NAME           [ukwcad36x]
Xstation 120
s  Serial Port
GL Emulation            [records]
Printer connection characteristics                                          
     BAUD rate                                        38400               
     PARITY                                           none                    
     BITS per character                               8                     
     Number of STOP BITS                              1 

The customer then advised that he attached an ASCII terminal to the
Xstation and attempted to "print" the the screen at 38400 and would see
nothing. He then removed the ASCII terminal and again attached the plotter.
We then attempted to plot at 19200 bps, still nothing and the plotter's
light does not flash. The customer even has the option to view the plotter's
working, via a small monitor which is attached to the plotter. When
viewing the monitor, he will NOT see any "load" on the plotter. We then
setup the queue again, this time using the default of 9600 bps. Now
the plotter's light will flash, the "load" will show activity and the
plotter will print, yet it is very slow. 

ACT: The specifications for the Xstation120 do not allow anything
higher than 19200.  I confirmed the reactions of the Xstation120 when
it is set for 38400 on the serial port.  After data is sent to the
xstation at that baud rate, other baud rates will not work until the
xstation is rebooted.

ACT: this did solve the problem with matching the baud rate.  However,
now he would like to find out if there is any way to increase the data
transfer rate through this port.  He an I both saw that even at high
baud rates.. the actual data transfer rate was slow enough that when
using a terminal, we could watch it paint the screen.

ACT: turns out this is just a limitation of the xstation 120.  This is
due to the paging traffic that the 120 and 130 have to do with the

Support Line: Plotter attached to Xstation will not plot at 38400 baud ITEM: BI8736L
Dated: May 1996 Category: N/A
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