Null modem cables

[Managarm]

I hope someone can help. I've got two Amigas, my main one which is an A1200 with HD and the old one, A500+/A570. I've recently got a load of cd software - Aminet and the Fred Fish collection. What I've been doing is saving the files to floppy on the A500 and then loading and installing the software on the A1200. This is getting to be a pain.

So I thought of getting a null modem cable and transferring files that way. I assume I'll need some software (that hopefully will be on the Aminet or Fred Fish CDs). How easy is this to do? What is the transfer speed like? (I've heard the serial port is kind of slow.) Also how easy are the cables to find?

[melott]

Hmmm...  :-)
Its really quite easy. You have 2 choices, ParNet,
using the parallel port, or as you suggested serial
port.
I would probably go with serial. You probably can still
pick up a Null Modem at Radio Shack for just a few dollars.
Probably less than $10.00. Then all you need is a couple
serial cables and a Term prg. I used JR Com to Null Modem
between a PC and My A500. Worked quite well and is very
fast. (as fast as the serial port will run).
Any term prg should do (aminet).
All you do is run the term prg on each machine and do an
Upload/Download. I did this with harddrives on both machines
but if one of the machines if floppy only it will run only
as fast as the floppy will allow.

[Managarm]

Great, thanks for that. Would any null modem cable work or are there different types? I only ask as I typed it in on Ebay and this came up:

http://search.ebay.co.uk/null-modem-cable_W0QQsojsZ1QQfromZR40

I'm sure there must be a networking program on one of the CDs. (After all there's 6000 programs on the Fish Disk alone.)

[melott]

Yes .. any of those will work.
The one I have is a 23 pin but it doesn't matter which
you use. It just has to mate with the cables. And since
the ports on the Amiga are 23 pin thats what I bought.

If you've used any term prg to log onto a BBS then that
term will do. Its very simular to how the old BBS's worked.
It may take a few minutes of fumbling around to get the
routine but once you do it you'll find it very easy.
You just set one machine (term) to upload and the other
machine (term) to download. Them on the upload machine
you send the file, and the other will download to where
you want to store the file.

[Joshua]

melott wrote:
Yes .. any of those will work.
The one I have is a 23 pin but it doesn't matter which
you use. It just has to mate with the cables. And since
the ports on the Amiga are 23 pin thats what I bought.

Just to avoid confusion, the serial port is 25 pins (the RGB port is 23 pins on the Amiga).  Hate for "managarm" to go looking for a 23 pin NULL modem cable

[Floid]

melott wrote:
Hmmm...  :-)
Its really quite easy. You have 2 choices, ParNet,
using the parallel port, or as you suggested serial
port.
I would probably go with serial.

This seems like a good overview of the options -- actually a few more than I was aware of, with the PC2Amiga hack and so forth.

Serial is a good thing to understand, because just about any machine can be wired up by good ol' RS-232.  However, in this particular Amiga-to-Amiga case, I gather ParNet has one heck of a speed advantage -- at least 20K/s (I assume those are bytes), while you'll peak at about 14K off your average PC UART, and apparently a good bit less (4-5K?) on a stock Amiga.  This might matter 'a lot' if you're talking about trucking CDs worth of stuff back and forth.

From there... if it were me, yes, I'd be drawn to the idea of using a PLIP link, while accepting how much of a pain in the *** that's bound to be.  In theory, this would let you do everything over IP, "the way it's meant to be,"* and give you the option of routing the older machine onto the Internet itself, through the 1200 with a proper "cheap" network card, etc.  In practice, this requires you to have enough experience with IP in general for that idea to even sound attractive, what with trying to chase down appropriate stacks and so on.

If you do go for a serial link, the "NCP" option sounds like an interesting (and presumably not-expensive-or-rare) way to make it more convenient than juggling terminal programs at both ends.  Nothing fancy about it, as a Psion owner I can say it's just a simple protocol for file and printer sharing across a serial link, nothing to do with IP or anything complicated... but it looks like the Amiga implementation lets you access things as devices, which would make it much more like having a "network" than two machines hung together by shoelaces and twine.

Good luck! [...and let me second that, yes, the cable you're looking for should have 25-pin ends, if there was any doubt.]

*Of course, now everyone will sneeze at the way IP has overhead and so forth... because not everyone thinks that one-protocol-everywhere is the way it was really meant to be.  But that's kind of the point of it, it lets you unify everything on one stupid protocol (and "internet") instead of many different ones.

[melott]

I stand corrected on the serial port, yes its 25 pin. sorry.

But what he wanted, If I understand correctly, is a quick way
to transfer files between the 2 machines.
Null Modem is the quickest and easiest way I know of.
I've never used a ParNet so I can't really comment on how
easy or hard it is to set up. Null Modem is quick and easy.
If he wanted to have them connected all the time then
maybe ParNet is the way to go.
My memory may be faulty here because it was about 15 years
ago that I was doing this between a PC XT and an A500.
Both had harddrives and it seems to me that the serial
connection ran at about 115k.
I ran a BBS on the PC XT and did alot of transfering of
files between the machines.
But as I said, that was about 15 years ago, memory can fade.

 :-D

[Managarm]

Just wanted to say thanks to you all for your help. My days of messing around with floppies will soon be over.

[jj]

the serial port on an amiga 1200 runs much master than a standard serial port on most pee cee's

[Ilwrath]

Null Modem is quick and easy.

Well, quick and easy in comparison to sneaker net, for sure.    ParNet is faster than a Null Modem, but not by too much, and ParNet is a bit of a fragmented system, as IIRC, there were two different revision ParNet cables, and one worked much better than the other.  And worse, I forget which worked better, and neither are real easy to find nowadays.  Null modem is the safer choice.  And ANY of these solutions are painfully slow in comparison to something like a 2065 ethernet card.  ;-)

the serial port on an amiga 1200 runs much master than a standard serial port on most pee cee's

This is wholly incorrect.  Even the serial port on my oldest PC (Pentium 1 @ 133mhz) soundly trounces any Amiga serial port.  The Amiga serial port is routed through the chipset rather than a dedicated UUART chip, and is slow as heck.  The maximum you can expect without errors is 19,200.  (And, honestly, only my 4000/060 could sustain that -- my A1200/030 had troubles at that speed.)  If you use an error correcting system (highly recommended, even at lower than 19,200!) you won't benefit much by trying to go to 38,400 as the error/retry rate starts climbing high enough you get a slower overall throughput.  

[patrik]

@Ilwrath:

If you have an AGA based Amiga with an accelerator and use =comm/term]Term and 8n1.device you will most likely achieve 115200.

The only case I have found this to not hold true is if the cpu has far from good bus-access as the case is with the A3640 cpu-card.

If you haven't got a RTG-card, don't use more colours than necessary on Term's screen, 4 colour or less is recommended.

Btw, I have never tried with anything else than a regular 7-wire nullmodem cable.


/Patrik

[Ilwrath]

Hmm... Don't think I've used 8n1.device.  Does it help THAT much, though?  I used a replacement serial.device that I think was called "newserial.device" back when I used serial ports, and it helped, but not a lot.  It allowed my A1200 to run at the 19,200 baud to properly support my (then blazingly fast and eye-wateringly expensive) USR 14.4k modem.  But that was about it's limit.  I never did get that A1200 to support 38.4kbps very well.

And I had to get a ASDG 2 port serial card for my A4000 to get it to work well with my USR 56k modem.  I couldn't push the 4000's built-in serial port past 38.4k reliably.

[patrik]

@Ilwrath:

It helps a bit, but it depends alot on how demanding communications software you are using. If you are going for example browse the web on an AGA Amiga in more than 64 colours, I wouldn't bet for more than 38400-57600. In this case though where you simply are going to transfer files over a nullmodem cable, then Term in combination with 8n1.device is a real rocket. And before anyone asks - NComm is slower and quite buggy too.


/Patrik

[Managarm]

Now that I'll have the two Amigas networked, does anyone know if I' be able to connect it to a Spectrum +2?

[Managarm]

Now that I'll have the two Amigas networked, does anyone know if I' be able to connect it to a Spectrum +2?