Re: iMac to GS

["william strutts" <wrstrutts1@nospam.home.com>]

"Byron Desnoyers Winmill" <wbdesnoy@acs5.acs.ucalgary.ca> wrote in message
news:9ngdju$h6o$1@nserve1.acs.ucalgary.ca...
> william strutts (wrstrutts1@nospam.home.com) wrote:
> : You can't hook two modem up and expect them to talk. They
> : need to be connecting through the telephone.
>
> Actually, many modems can be connected via a dry line.  That is what the
> "atx3d" command is used for.  "ata" simply answers the phone, and is not
at
> all concerned with the ring.  I used to use this all of the time: a friend
> and I would be chatting about something on the phone, we would have our
> modems connect to transfer a file, then drop carrier to chat further.  All
> of that was done without hanging up the phone, nor redialing.

I have never heard of this command.  AT stands for "attention" and
anything after that tells the modem to carry out a command.  You
would have to command the modem to answer the phone but
without a ring....I don't know how that would work.  Another problem
is that a modem normally won't send a carrier for handshaking unless
it detects the phone line being picked up. (ie it stops ringing)

> Since "ata" simply takes the phone off hook and tries to establish a
carrier,
> it should be possible to connect two modems even if on of them does not
> support the "atx3d" command.
>
> : However, you might try turning off carrier detect on the answering
> : modem and see if that works.
>
> IIRC, carrier detect refers to the signal between two connected modems.
It
> has nothing to do with the telco, aside from it being transfered over the
> telephone lines.  (Ie. the telco does not provide the carrier signal.
> Perhaps you are thinking of the dial tone?)
>
The carrier is a base signal that the modem sends to establish
connection with another modem. It is a handshaking signal.
Many modems won't respond to another modem if the
carrier signal is missing. It is a long steady signal and not
the warbling signal that you typically associate with data
transfer.  The answering modem then sends it carrier and
then they negotiate the transfer rate and parameters.
--
--
William R. Strutts - wrstrutts1@nospam.home.com - Whatever!

C'est moi!  http://www.facelink.com/wrstrutts

Just hacking away...

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