Chris_F_Chiesa@cup.portal.com (04/10/89)
Gil --
This is ridiculous! Every time you write me I write back, and every time
it bounces. The only way to get through to you seems to be to post here. No
bounces, who knows why!
The following is the complete text of what I've been trying to send you for
the past five or six weeks, so I hope it goes through.
For those of you interested, this document contains the details of con-
structing a null-modem cable and transferring files from an Atari to some
other computer, without using modems. You may THINK you'll "never need that,"
but - trust me; you WILL someday wish you'd saved this! :-)
-----
Subject: Re: Transferring files, ATASCII <--> ASCII, et al
Lines: 206
Date: Sun, 12-Mar-89 12:05:50 PST
Hi Gil!
Sorry for the delay in this reply; I've been busy hosting friends from
out-of-state for a week or so!
I'll get to the file-transfer stuff in a sec; first though, a few words
about Portal.
Judging from the wording of your inquiry about AI openings, it seems you
are thinking of Portal in the same light as most of the other nodes on this
Net -- a company (or perhaps a school) doing business, with all the users
being employees, students, etc. All in all this is quite a natural assump-
tion -- I, in my student days, never thought otherwise myself.
However, our common conception turns out to be a MISconception! Portal
is actually a "subscriber" service -- a "pay as you go" system, if you will.
It seems to be run by a relatively SMALL group of people; I'd say nearly ALL
the 'username@Portal' postings you see, are from SUBSCRIBERS such as myself!pag
Therefore, I myself have nothing whatsoever to do with Portal per se -- it
is merely my access point to the Net, at the present time. I don't even LIKE
it all that much, for various reasons not apparent on your end... But I
digress. I will attempt to forward your compliments about Portal users to
the appropriate system managers, so that they will know that you have been
kindly treated by Portallers in general.
Now, about file transfers! I'll have to pop out of my terminal program
for a moment, to find the files I originally tried to send to you and Mr.
Bartlett, way back when... hang on!
-----
Okay... here's the FIRST posting I tried to send; I can't find the second --
maybe I lost it... but I should be able to re-create it and make the same
points again, after this first "article."
---
Gentlemen -
In regard to your file-transfer yearnings, allow me to recommend a simple
item known as a "null modem" cable. This is a cable which, when connected at
one end to computer A's serial port, and at the other to computer B's serial
port, makes EACH computer "see" the other as a "modem connection." You could,
if so inclined, run a BBS (Bulletin Board System) on computer A, and "log into"
it from computer B. Or, you can run a terminal emulator on each, and "talk"
back and forth... and if those terminal emulators both happen to support the
same "file-transfer protocol," VOILA -- you can transfer files!
The construction of such a cable involves running at least THREE conduc-
tors (wires) between the computers: "SEND data," "RECEIVE data," and "Signal
GROUND." These are typically assigned to pins 2,3, and 7 of a standardized
"DB-25" (the type of jack) or "RS-232" (the 'standard' that defines the sig-
nals) plug or jack. Obviously, you will need the appropriate "plug" or
"jack" to "mate with" your computer's existing serial port, whatever that may
be; if you are not using the "standard" 25-pin connector (you may well not
be; in fact, your computer may even require an extra circuit board to do
serial I/O), consult your manuals to find the "pinout diagram" of the serial
port, and connect up a cable as follows:
Computer 'A' end of cable Computer 'B' end of cable
"Transmit Data" (or "TD," ----\ "Receive Data" (or "RD,"
or "SEND data") ----/ etc...)
"Receive Data" ----\ "Send Data"
----/
"Signal Ground" (or "GND," ----\ "Signal Ground"
or "Data Ground") ----/
(If you ARE using "standard RS232 25-pin" or DB-25 plugs/jacks, this may
be expressed in terms of "pin numbers" (these are molded, very small, next
to eack jack-pin or socket-hole) as:
pin 2 ---> pin 3
pin 3 ---> pin 2
pin 7 ---> pin 7
)
It is possible that your particular computer may require additional con-
ductors (wires) or signals; what I have shown is extremely MINIMAL and may
need to be extended. If you get as far as what I've shown, and you plug
it into both computers, and they still won't "talk" to each other, contact
me again.
I would like to suggest that you DON'T write to me at the address that ap-
pears with this message! That is the address of my "school" account, which
remains in existance even though I graduated some time ago, and which I rarely
if ever log onto. I have subscribed to (cough cough) "Portal," however, and
can be reached there by sending E-mail to
Chris_F_Chiesa@cup.portal.com
If that mail bounces, THEN try sending here -- but the turnaround will be a
lot longer!
Anyway, that covers making the cable. As for terminal programs, try to find
a program for EACH computer that supports "file transfer." This is DIFFERENT
from "ASCII capture," so be sure you've got some sort of "protocol" besides
just ASCII. (That keeps your files from being garbled if there's "interfer-
ence" on the line; admittedly, much more of a nuisance while using a modem
than with a direct cable, but essential if you want to transfer anything other
than plain text. I regularly transfer executable "binary" files, for instance.)
Some popular protocols that you should be able to find are "XMODEM" and
"Kermit" -- I know for a fact that BOTH exist for the Macintosh and the Atari,
and that Kermit exists for the PC, so you should be able to get going with
this arrangement in very short time.
It occurs to me that I may have "talked over your head(s)" in some areas,
or glossed over others. Please let me know how you make out with this,
whether you can or cannot get it to work. I didn't notice where either of
you are located physically, but for what it's worth I'll tell you that I am
in Rochester, NY, and can be reached by telephone at (716) 342-5914. (If
that's busy, you can TRY (716) 544-5188. These are both HOME numbers; I
usually work 8-5 PM, Eastern.
Good luck to you both!
Chris Chiesa
-------
Okay, that's the FIRST thing I wrote to you. The second, sent a day or
two later, came after some thoughts on the subject. The gist of it was as
follows...
It suddenly occurred to me that if you are using an Atari 8-bit computer,
some of the previous message may be misleading. Specifically, the references
to "your computer's serial port" may be misleading. On the Atari, the only
built-in "serial port" is the 13-pin "SIO" port. This is *NOT* the "serial
port" of which I spoke in the null-modem-cable discussion (above)! Atari
did their serial I/O differently than most computers, probably because they
were "there" fairly EARLY in the field.
In order to apply the "null-modem cable" idea to an Atari 8-bit computer,
you'll need an additional piece of hardware of some kind, to transform the
Atari SIO-port signals and lines (wires) to those compatible with other com-
puters. This is the function performed by the Atari 850 Interface, or the
"P: R: Connection," or similar devices you may have heard of.
It might help if you think of your Atari-plus-external-conversion-hardware
as ONE unit; it doesn't matter WHAT the "external conversion hardware" is,
as long as its OUTPUT is compatible with the RS232 standard as briefly covered
in the first message. In "computer A, computer B" terms as used in that
message, it would look like this:
+---------------------+ +------------+
| Computer A | + Computer B |
| +-------+ +-----+ | | |
| | Atari +---+ 850 | +------------+ |
| +-------+ +-----+ | N-M Cable | |
+---------------------+ +------------+
What this shows you, basically, is that "Computer A" from the first posting,
consists of the Atari PLUS an 850 Interface or equivalent signal-conversion
hardware. Feel free to ask any questions you may have, of course.
A second consideration of file-transfer between Atari 8-bit and other
brands of computers, arises from a point of Atari internal design. Namely,
Atari took the liberty of redefining some of the standard ASCII character
codes, to the point where every OTHER computer's end-of-line character,
the "Carriage Return" (ASCII 13), is of no special significance, and the
"ATASCII" (Atari ASCII) character 155 is used as the end-of-line marker.
This means that if you want to transfer text between Atari and other computers,
you need to allow for, and perform, the conversion from standard ASCII, to
"ATASCII". This can be either very tricky, or very trivial, depending on
how you proceed.
Fortunately, most terminal (and file-transfer) programs for the Atari 8-bit
computer, have long been aware of this need, and have facilities build right
in to perform the conversion DURING file-transfer. A "switch" for "ASCII/
ATASCII" usually appears somewhere, either on a menu or as a command or
option at a prompt. If you use this switch correctly, you need never do
any other conversion; on the other hand, if you DON'T use it, use it WRONG,
or use a program that (heaven forbid) DOESN'T HAVE it, you may find yourself
trying to word-process what looks like a lot of gibberish. In a sense, this
is just an "extension" of the need, in some file-transfer protocols, to "tell"
the program in advance whether you will be transferring "text" or "binary"
files. In fact, in Kermit65 on the Atari 8-bit, in addition to the usual
"set file-type binary" and "set file-type ascii" setup commands, there is
also a "set file-type atascii" command to do this very thing!
(And, for the record, in "850 Express!" which implements XMODEM file-
transfer, there's an option on the menu screens for "ASCII" vs. "ATASCII"
mode. Unfortunately, it affects terminal mode as well as transfer mode,
with the result that you may need to toggle back and forth a lot, but if
you "play" with it you should be able to find a combination that works.
-----
Okay, Gil, that's the gist of what I said last time; I hope this reaches
you! Please feel free to contact me by whatever means are convenient, if you
have questions. I used to have a job, at school, helping people all over
campus, and I miss it, so here I am all revved up with no place to go!
Good luck!
Chris Chiesa