HP75D and data acquisition unit HP3421A

[J-F Garnier]

(02-28-2024 08:37 AM)hesc Wrote:  In my HP75C a data communications ROM is installed, 00075-15035. In my other HP75D I see 2 empty slots and the third one is occupied by a rather large tele communications unit around the HP75D, I believe.
So, I think indeed, the missing IO module in both HP's may be the problem...

(02-28-2024 11:14 AM)Dave Frederickson Wrote:  If you don't have an I/O ROM you can use the I/O Utilities.
https://www.hpmuseum.net/display_item.php?sw=489
https://literature.hpcalc.org/community/...-io-en.pdf

I just realized that the I/O utilitiy commands (SENDIO, ENTIO$, SEND?) are included in the Data Communications ROM !
It is the way the BASIC programs inside this ROM communicate with the HP-IL modem and printers.
So Sylvain's program can be entered and used with just your Data Comm module inserted:

(03-03-2024 08:26 PM)Sylvain Cote Wrote:  So here is the modified program listing

Code:

 10 ! DCV HP 75/3421A
20 REAL V
30 ASSIGN IO ':E1'
40 CLEAR LOOP
50 SENDIO ':E1','LAD#','DCV5'&CHR$(13)&CHR$(10)
60 V = VAL(ENTIO$(':E1','TAD#,SDA'))
70 DISP V
80 END

Let us know if this works.

J-F