Conference hydra::amiga_v1

       Kristine, what I've seen regarding ribbon cables is that you
       should avoid them at all costs due to the fact that they aren't
       shielded and therefore can cause you extreme grief interms of
       interference.
        
       I am using a DF112 with no problems.  I just got a Scholar which I
       will be hooking up tonite.  When I have everything torn apart, I
       will make note of the pinouts and post them for you.  
        
       I have ended up making all my serial cables (to modem and LA50),
       as I never could find a DEC standard cable that fit the bill
       exactly (on the other hand, I really didn't look too hard).  I
       always started with a DEC cable, but then ended up cutting off one
       end or the other and replacing it (them) with a DB25 connector
       from Radio Shack.  As stated, I may not have looked hard enough
       and there may indeed be a DEC cable that will fit the bill without
       modification.  I simply made do with what I found laying around
       the office.
       
       Once you have the pinouts, you can check the DEC cables and see if
       one matches or which one requires the least amount of modifying.        
        

       Art Gosling
        

    I am using a DEC Scholar with a RS232 straight-thru ribbon cable
    from Radio Shack. I have had no interference problems whatsoever
    -- and I have several hundred watts of UHF and VHF RF radiating
    just a few feet above the computer from my radio antennas.
    
    Of course, be sure to snip the pins that contain Amiga-specific
    voltage on the RS-232 port. (refer to your Amiga Owner's manual
    for pin-outs)
    
    Paul
    
    

    By the way, at under $400, the Scholar is a superfine piece of modem
    hardware. Anyone know if it is DEC-developed product?

        Kristine, as promised here is the pinout of the cable I put
        together.  As you can see there is nothing magic and I believe a
        plain old BC22 will do the trick.  As I now recall, I build my
        own cable because of connector imcompatibility problems with the
        cable I managed to find laying around (needed male connectors and
        the cable had female - something like that).
        
        Anyway these are the pins I have connected:
        
                      amiga  modem
                        1-----1
                        2-----2
                        3-----3
                        5-----5
                        6-----6
                        7-----7
                        8-----8
                       20----20
                       
        Art

A cable with less pins also seems to work fine.  I connect my Amiga to
my (well, my cost center's) scholar modem using a cable that only has pins
2, 3, 7, and 20.

    No, I haven't forgotten my manners.  Thank-you all for your replies.
    It's been a while collecting a modem, getting Dave Wecker's great
    
    emulator and having a coworker create me a cable (thanks to Art
    G. for the pin layout).  After finding a loose fuse, I'm happy to
    say I'm online!  Thanks to you all. KT

    Could someone please make me a picture that shows how the pins are
    numbered on my cable?  It's not in the modem manual or my amiga
    hardware manuals.  

All of my RS232 connectors have numbers engraved next to the pins.  They are 
however VERY small and hard to read.  But if you look close you will probably 
find them.  

	Paul

Re: .8

And use a very bright light: those RS 232 pin numbers are small!

    
                  -+--+--+--+--+--+--+--+-----------------  
                  \1  2  3  4  5  6  7  8  9  10  12  13 /
                   \14 15 16 17 18 19 20 21 22 23 24 25 /       
                    ------------------+-----+-----------
    
    The +'s should be present and straight through
    

When I had a DF112, my modem and Amiga got alone just fine.
Ever since I received a df224 however, there's some feedback
of some form.  It doesn't appear harmful, since I've been running
with it for 3 years, but I'd like to fix it now.

My modem cable has the following pins connected:

12345678 (okay so far, standard signals)

12 15 17 19 20 22 24

That's it.

Pins 14, 21, and 23 are the ones which carry unusual voltages,
according to my hardware manual, which may or may not be correct.
There isn't even a year next to the copyright notice, it's
old and possibly pre-release.

Which pin(s) do I need to disconnect to keep my modem from
causing audio (!) feedback through my monitor?

(Yes, as soon as I hook up the modem to the amiga, a whine
 comes from the monitor.  Further, one I establish a connection
 with a communications program, the whine decreases in intensity
 (somewhat) and changes tone by one octave!

I've worked around this little annoyance for 3 years simply
by turning down the volume.)

Any clues?  I want to hook up my amiga to another machine,
and I don't want to accidentally fry any circuitry because
of unwanted voltage on the lines.

Dave

    I can't find a pinout of the DF224 anywhere in the owners or
    installation manual, but I'd bet that following pin is the culprit:

    15 - AUDO - Audio out of the Amiga

    Pin 16 is the Audio into the Amiga (AUDI), but that one's not on your
    list. From memory, I believe you should only need pin 20 in addition to
    the above mentioned pins 1 through 8. Assuming you're still using your
    A1000, I'd disconnect pin 15 from the Ami end of the cable, otherwise,
    a BC22E works quite nicely on an A2000 (probably on an A500 also).

    Hope this helps,

    Pete

Audio out ?

I've noticed that before and never remember to ask. Is this
wired up to anything ? Is it useful/usable ?

Regards
	Mike

re: .12

Thanks, I'll check out/cut those pins.  Certainly shouldn't
hurt the serial communications.  I'm just trying to keep
cut pins (and my of late high potential for messing up
computer systems and software) to a minimum.

Dave

    Dave,
    
    Since you appear to be running an A1000 (from your "memoir" note),
    beware that the serial port has several nonstandard signals on the
    pins.  Reply .4 to this note seems to be about right, and gets rid or
    most of the higher-numbered pins in your cable.
    
    Wes
    Who luckily never fried his serial port

Followup:  removing pin 15 (AUDO - audio output from amiga)
solved the audible feedback problem.  Not my monitor is nice
and quiet when I hook up the modem.

Dave