HP Forum Archive 14

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HP82164 HPIL-RS232 connection to PC Message #1 Posted by Nick Nicholas on 24 Dec 2004, 4:32 a.m. With regard to the article at http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=118 regarding the connection of the HPIL-RS232C to the PC, I would appreciate clarification on the following based on my background of no exposure to serial interfacing. The purpose of the special adapter is to correct the positions of the pins of the HPIL RS232C interface to that expected for a RS232C interface for a PC (DTE device) as well as to provide for the null modem functionality of connecting two DTE devices serially. The diagram on the above web page indicates the corresponding pins to be connected from the HPIL RS232C interface to the PC (DB25-S). I would like to use a 9 pin serial cable to the PC, instead of the 25 pin cable. All the pins are accounted for on the 9 pin serial cable except the protective ground, pin 1. Is this pin on the HPIL RS232C interface required to be connected to the PC? Can any damage be caused to the PC or the HPIL RS232C interface if the pin connections are incorrect in the adapter? Does this pin assignment work for the HP 71B connected to a PC through the HPIL RS232C interface?

Re: HP82164 HPIL-RS232 connection to PC Message #2 Posted by Tony Duell on 24 Dec 2004, 6:12 a.m., in response to message #1 by Nick Nicholas As the author of that document, I think I can answer some of your questions : (This doesn't apply to one of your questions, but I found it best to ignore the jumper plug inside the 82164 -- leave it at the DTE position -- and make up the right external cable. That jumper does some rather odd things!) Now, for 9 pin serial ports. My PC has such a port. I just used a normal 'Modem' cable with a DE9 socket on one end (to fit the PC) and a DB25 plug on the other (to fit a modem). In fact I use that cable with my dial-up modem too. If you want to make your own cable, just match up the signal names. You can ignore pin 1 (Protective ground) if you like. Some cables wire it to the overall cable shield ('screening braid' in the UK), and connect that to the shell of the DE9 (9 pin) connector, and thus to the PC case. The RS232 interface is very tolerant of misconnections and it's unlikely you'll do any damage if you get the connections wrong (I won't say "can't do any damage" because somebody will find a way :-)). Even if you do damage something in the 82164, the RS232 interface chips are the standard 1488 and 1489 ones that are easy to get and easy to replace. Yes, it does work with the HP71B. I've used it with that machine. I've got linux software (part of the 'LIF Utilities for Linux' available from the HPCC web site) to transfer files to/from an HP71B. It should work with an HP75 too, although you won't be able to transfer files directly (you'll have to write a BASIC program on the 75 to read in data and store it in a text file). I've never tried that, though.

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