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NeXT
December 22nd, 2013, 06:03 PM
So I have the HP85, the 82939A serial card, the 7475A serial plotter and the Printer/Plotter option ROM.
Both the adapter and the plotter are set to 9600/8/n/1 and are directly connected with a gender adapter in the middle.

My problems seems to stem from the ROM only documenting how to work with HP-IB devices. It gives no mention what to do if you have a serial interface and a serial plotter.
As a result I can''t seem to RTFM and be at lest printing the screen immediately.
Adding to the frustration, NONE of the basic statements for the serial card and most of the statements for the option ROM don't seem to work. It's either error 89 (invalid parameter) or error 84 (excess characters). Wtf?

g4ugm
December 23rd, 2013, 08:14 AM
Does the ROM even work with a serial plotter?

You will also almost certainly need a null modem lead. Pin outs should be in the operation and integration manual..

http://www.hpmuseum.net/exhibit.php?hwdoc=74

NeXT
December 23rd, 2013, 09:40 AM
Yeah, I looked through the manual for the serial card. I can do a fair bit of repinning and jumpering in the card itself (found out it does current loop too, WOO-HOO!)
Unofortunately I've yet to come across anything that says "YES". One guy years ago said you had to use PLOTTER IS 10 but this seems to lock the machine up.

g4ugm
December 23rd, 2013, 09:59 AM
Reading the serial card manual from

http://www.series80.org/Manuals/index.html#Section-InterfaceAdapterManuals

I can see that the default address for the serial card is port "10" so you do "PLOTTER IS 10" if the card is address 10.

I would expect it to lock up if there is no card on 10 or something is wrong with the cable.

Do you have a meter to check the voltage on the RS232 lead? Pin-7 is ground. Either Pins 2 or 3 should have a -ve voltage on the socket when measured against pin 7.

Check both the plotter and the HP-85. If the same pin has -12v you need a null modem cable.

NeXT
December 26th, 2013, 08:29 PM
Actually, you are right. Normally my cable is Type 1 which is for attaching consoles but repinning to type 2 seems to make it a null modem cable and at the very least stops the system locking up.

Moving onwards I must of been tired as I completely missed the fact that the plotter ROM documentation was for the HP86 and was a completely different part number (00087-15002 instead of 00085-15002) so my errors are most likely because I'm calling commands my ROM simply does not have. In fact I can't seem to find the manual anywhere.

NeXT
January 19th, 2014, 04:59 PM
Just to wrap the thread up I continued researching and it's not worth trying to attach a serial 7475A to the HP85. While it will technically work a lot of applications are expecting the plotter to be HP-IB. and I simply don't have the time to go over everything I want to use and modify it. I'm better off using the 9816 instead.

inakito
January 28th, 2014, 10:17 AM
I did some experiments myself to try to output plotter output to the serial port, using the command plotter is 10, and was unable to see any traffic on the serial side. I belive there is some sort of starting/ready check that is sent to the gpib or is managed in a way that is not serial compatible. Plotter output in the hp85 is converted to hpgl commands on the fly, so if serial is supported there should be some output visible on the serial output, which i did not see. What i found is that redirecting plotter output to device 10 (serial) the plotter functions get locked waiting for something to happen.

Martin Hepperle
May 4th, 2016, 04:08 AM
I did some experiments myself to try to output plotter output to the serial port, using the command plotter is 10, and was unable to see any traffic on the serial side. I belive there is some sort of starting/ready check that is sent to the gpib or is managed in a way that is not serial compatible. Plotter output in the hp85 is converted to hpgl commands on the fly, so if serial is supported there should be some output visible on the serial output, which i did not see. What i found is that redirecting plotter output to device 10 (serial) the plotter functions get locked waiting for something to happen.

Hi guys,

this thread is a bit older but did not find a happy ending.

Therefore I can share my experience:
the solution is rather simple:
- of course use the proper cable (as per plotter documentation), test with some simple direct HP/GL output e.g. with PRINTER IS 10 @ PRINT "PAPU0,0;PD100,100;PA" to make sure the cable is correct.
- then read the plotter documentation about setting up the interface with ".I" etc. commands so that it output terminates replies with a CR/LF. This is important! The info is also printed on the back side of the plotter reference card.
- the HP-85 plotter ROM asks the plotter for some status information when the "PLOTTER IS" command is executed. You can see this e.g. when you connect a terminal to the serial cable.
The plotter MUST(!) send its reply with a CR/LF Terminator sequence, otherwise the plotter ROM waits for this terminator forever and the HP-85 hangs inside an infinite loop.

Good luck,
Martin