HP-71B-HP-IL/RS232 vs Carriage Return


I have a HP-71B and the HPIL/RS232 successfully transferring data and files to/from my PC. Im using an old x286 machine and ProcommPlus (for DOS) as a host. I also have all the documentation for the calculator and the interface.

The only problem left to conquer is the carriage return (CR). My PC will not recognize the <cr> that the -71B generates. I have found the command setup for the interface to delete/insert (ie:change) the <CR>, Im just not sure what ASCII characters I should change. Anybody know what the trick is? I am attempting to transfer BASIC files (transformed into text) over to my PC.

Thanks in advance,

Doug Thomas


I am not sure my quick answer is right, but you may have to include both the <CR> (carraige return) and <LF> (line feed) asciss character in strings. Many years ago I programmed a lot of HP equip and this was usually required to get data out correctly.


The 71B does not generate a <CR>. It uses UNIX convention, where the end-of-line character is a <LF> instead of <CR> <LF>, like in modern PCs.

Ever wondered, why there's a BINary and an ASCII mode in all the ftp programs? That's the reason.

BTW: the development of the 71B ROM was made on a UNIX workstation (a HP 9300 machine), so the developers were used to it. PCs were not very common in the glory days (the 71 was developed 1983-1984). For example the 71B Text Editor Module uses regular expressions for search and replace. The editor is similar to EX (which preceded VI).

There's a lot of conversion utilities on the net and it should be easy to write one on the PC (for use only with Text files). I can see, if I find something on my Winchester (hey, nice old word for a HDD, I just felt I had to use it now).

I know, that for printing you can use the ENDLINE string to specify <CR><LF> (ASCII 13,10), but I doubt, that TRANSFORM will use these settings.


Well....after much pondering...I figured out a way to get what I wanted. Instead of trying to tackle the CR/LF issue, I just did the following.

1. Initialized the HPIL/RS232 interface from the Hp-71B.
2. Bring up my host application (ProcommPlus for DOS).
3. From the HP-71B, issue this command: PRINTER is :RS232
4. From the HP-71B, issue this command: PLIST FILENAME

The file had previously been transformed from basis to text.
The text file is transferred over to my host application and I captured the whole thing.

If anyone needs help with the HP42461A interface, drop me a byte, Ive been using one a lot for the last month or so.

Doug Thomas

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