COM cards

Hi,

I have tried to read the digest, - all day long, - each time I sit
down with it, I get interrupted. ( I have a friend that calls me
about all sorts of things - he is trying to set up a network, then
I have written to several regarding Varkon )

Okay, first Andrew:

No, not all computers have opto isolators built into their I/O
cards ..... and this is not the parallel port !

I gave you a simple description about the current loop, but before
that one, I told you about the serial card, ( COM1 or COM2 in DOS )
- and if you have an old IBM ISA card, or a clone of those - then
you have an opto isolator already on that board. This is because
those card had both, RS232 and current loop. You have to select the
mode, by turning around the IC looking part in the socket.

I would send you a drawing or picture if I could, but the Win98 box
is out of order, and I need that in order to scan any picture. Is
there anyone else that has something to help him with ?

I have used it as a communication link to other systems I have
built, but many years ago, - I did use it instead of a tape driver
for a NC control, and some of the other on this list have said (
I think Jon Elson ) that they had some small code that would emulate
a tape drive. ( I don't have my code anymore, or can't find it )

But you have the original tape drive ?

If so, check the wiring. If it is possible to use it, then there
might be some code on the tape. If it is wired as a current loop,
then you may connect it to the interface I described, and dump the
contents of the tape to a file on a computer. If you don't know what
syntax the code you need to send to your machine, then you could
inspect that file. This could be valuable if this is the only
information you have to go by.

Do you have user manuals for the machine ?

I did ask you last time - where do you have the photos and such of
this thing ? ( I have waded through the digests, and I can't find
the URL )

Anyway - the idea is to use a computer instead of the tape drive,
and feed the machine.

( A side note: I assembled a box once, which would convert between
RS232 and a Centronics parallel port. I hooked this on a printer
port, and downloaded it on a computer via this box. The machine
could print out the G-code to a printer, but I was writing a program
that could write the G-codes, so this way I got all the sample
files I needed. I used this to write the program I can't find. This
is 10-15 years ago, so I may have lost it.
This side note, was just to give an idea of how you can do things,
when you don't have other ways to get the info. )

I have to try to read the rest of the digest,

//ARNE