Date   : Wed, 15 May 1996 09:47:29 BST
From   : Willble! ere Elk! Elk! Wolverene! <osu036@...>
Subject: Correction to pins which were missing

Did you also include my other mail I sent with the actual connections which
I forgot?
i.e

       BBC             PC    
>   rts---          -rts
>           !                                 !
       cts--           -cts

>   data in (rxd)--------------     txd
>   data out (txd)------------      rxd
>   gnd-------------------------gnd

Another usefull thing you could also try if things stilll don`t work is to
ground all the other pins to casis ground on the pc

Connect all the unused pc pins to ground i.e  dtr /ri /dcd /dsr/ etc
on pc side
and thats it. Make sure you wire the domino correctly and it is inserted
the right way?
the diagram in the user guide shows the connector as if you where looking
towards the machine i.e seeeing the actual 
pins you should wire if you where looking at the sockect when opened up.

Also do not use 19200 baud on the bbc as things do`nt work.

Use same protcol on both machines i.e if comstar is used with x-modem this
is just plane x-modem not x-modem -crc.

Test all links with mutimeter and you should be fine.

> On Mon, 13 May 1996 17:08:18 +0200 Mark de Weger wrote:
> 
> > From: Mark de Weger <deweger@...>
> > Date: Mon, 13 May 1996 17:08:18 +0200
> > Subject: Unidentified subject!
> > To: bbc-micro@...
> > 
> > Hello everybody,
> > 
> > After this weekend's disaster with trying to connect my Beeb to a PC
(couldn't
> > get anything to work; still trying to work out what went wrong), I'm afraid I
> > need a little more help. The problem is there's two "schools" of people with
> > respect to connecting a Beeb's RS324 to a PC's RS232. My question is simple:
> > who is right?
> > 
> > 1. The "keep it simple" school says just to crosswire Data-In and Data-Out,
> >    to crosswire CTS and RTS and to connect the Beeb's ground to the PC's 
> >    oV. The wiring would be like this:
> > 
> >    PC                      BBC
> >    ==                      ==
> >    0V            <--->     Gnd
> >    Data In (RxD) <--->     Data Out (TD)
> >    Data Out (TxD)<--->     Data In (RD)
> >    CTS           <--->     RTS
> >    RTS           <--->     CTS
> > 
> > 2. The "it's more complex" school says that the Beeb's RTS and CTS pins have
> >    slightly different functions from the PC's. Instead, they say that
the PC's
> >    DTR pin has a similar function to the Beeb's RTS and the PC's DSR
has a similar
> >    function to the Beeb's CTS. Thus the Beeb's CTS/RTS pins should instead be
> >    connected as:
> > 
> >    PC        BBC
> >    ==        ==
> >    DSR <---> RTS
> >    DTR <---> CTS
> > 
> >    Then there's a number of "extra's" people have given:
> >    a. The Beeb's RTS pin should also be connected to the PC's DCD pin,
because the PC
> >       looks on both DSR and DCD for a response.
> >    b. The PC's RTS and CTS pins should be wired together.
> >    c. The PC's DCD, DTR and CTS pins should be wired together.
> > 
> > The motivation for the first "school" is that's simply the way it works
(according to
> > e.g. Gudmundur Thorsteinsson).
> > 
> > The motivation for the second "school" has been formulated by Paul Theobald
as follows:
> > > The BBC's usage of the CTS and RTS are (arguably) different from the
RS232 usage, and
> > > in fact more closely follow that of DSR/DTR.
> > 
> > Pete (pnt103@...) elaborates on that and also motivates
"extra's" 2a
> > and 2b as follows:
> > > The PC probably outputs a handshake on DTR and looks for responses
> > > on DCD and DSR. These tell the device connected to the PC that the
PC is active (DTR)
> > > and reply to say that the other device is present (DSR) and active
(DCD). Then RTS is
> > > the PC's way of saying it wants to send (not just receive) and CTS
is the other
> > > device's way of saying "go ahead"."
> > 
> > As Gudmundur pointed out to me, the "extra" 2c probably comes from wiring
up an
> > Archimedes to a Beeb, rather than a PC to a Beeb. (This is confirmed by the
> > comp.acorn.misc FAQ; the Archimedes had a broken serial port controller
which made the
> > extra wiring necessary.)
> > 
> > I'm sorry to bother you all again, but apparently things are not as simple
as it first
> > appeared. Is there anyone who can tell me who's right? (And if it's school
2, which of
> > the extra's a-c do I need.)
> > 
> > Thanxalot,
> > Mark.
> > 
> 
>                />      Christopher J. Thornley is OSU036@...
>   (           //------------------------------------------------------,
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>   (           \\------------------------------------------------------'
>                \>       Home Page :-http://www.bangor.ac.uk/~OSU036
> 
> 
> 
>