Re: [NTLK] DB9-to-MiniDIN Serial Cable

Dear all,

To come back to the technical issue:
According to the definition of a serial connection there is a so called DTE
and DCE.
Any PC or computer like is considered DTE,while a modem is a typical DCE.
(DTE = Data Terminal Equipment and DCE = Data Communication Equipment)
A (modem) cable (to connect DTE with DCE) was always with 1:1 pin
connections since the pinout of the RS 232 for DTE and DCE are DIFFERENT
such that each signal source is connected to the related signal sink (true
for both, data and handshake signals).

Having said that you may wonder what the Newt will be according to the above
definition:
Since it is definitely no MODEM (DCE) it can only be DTE.

Since you want to connect your Newt to a computer you want to connect a DTE
to another DTE. Looking at the connections: using a MODEM cable would mean
to connect the signal sources to each other and the sinks to each other.
It is clear that this will can never work.

So the solution was a so called NULL modem cable, that CROSSES send and
receive signals and also some of the handshake signals.

As far as MAC serial cables with one mini DIN connector at one end and one
sub-DB 9 connector on the other side are concerned, you cannot distinguish
between the Newt cable (with crossed signals) and a modem cable (with 1:1
connections).

Thus it is not easy to tell who is right.
There is only one thing that can be stated:
in case the cable works, it is DEFINITELY NO MODEM cable,
but who cares?

I hope this clarifies the issue.

Cheers,
Johannes

> -----Original Message-----
> From: newtontalk-bounce@newtontalk.net
> [mailto:newtontalk-bounce@newtontalk.net] On Behalf Of Frank Gruendel
> Sent: Tuesday, June 13, 2006 11:59 PM
> To: newtontalk@newtontalk.net
> Subject: Re: [NTLK] DB9-to-MiniDIN Serial Cable
>
> > an old Mac modem cable has the right pinout
>
> No, it hasn't.
>
> Frank

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