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From: elg@usl.UUCP (Eric Lee Green)
Newsgroups: net.micro.cbm
Subject: Re: 1670 modem
Message-ID: <930@usl.UUCP>
Date: Fri, 26-Sep-86 00:05:47 EDT
Article-I.D.: usl.930
Posted: Fri Sep 26 00:05:47 1986
Date-Received: Tue, 23-Sep-86 05:56:47 EDT
References: <784@mtund.UUCP>
Reply-To: elg@usl.UUCP (Eric Lee Green)
Distribution: net
Organization: USL, Lafayette, La.
Lines: 43

In article <784@mtund.UUCP> srm@mtund.UUCP (Steve M) writes:
>*** REPLACE THIS LINE WITH YOUR MESSAGE ***
>
>	I need some help in find out what signals are
>available out of the 1670 modem and going into the 1670
>modem. I have a C64 computer and I am tring to build a
>modem similiar to the 1670 modem. 
>the user port? I am trying to figure out how the phone
>number to be called is supplied to the 1670 along with
>the off-hook signal, speed indication, and ring indication.
>Please respond via email or on the net, as this info might
>be useful to many other C64 users.

The 1670 has no off-hook signal, speed indicator signal, or ring
indicator signal. All modem control is via Hayes Smartmodem-type
commands. For example, printing "ATH0" to the modem hangs it up, "ATA"
takes it off hook in answer mode, etc. When a person connects with the
1670, it prints "CONNECT" or "CONNECT 1200". If the modem answered to
get that connect, it prints the CONNECT or CONNECT 1200 in the old
baud rate and only then switches to the new baud rate, so that the
BBS program or software exchange knows what baud rate it's supposed to
be at and doesn't get out of sync. Finally, the modem will print RING
to the computer wwhen the phone is ringing, but usually you set it up
for the modem to answer by itself, and just look for a connect.

The only hardware signals used by the 1670, besides the power supply,
are  the recieve/transmit pair, and the carrier detect.
That's it. I've put a DTR signal onto my wish list -- I'd really like
to be able to hang up the modem by poking it off, as vs. printing "+++
ATH" to it inumerable times until it decides to hang up.

Note that the above is very BBS program oriented, since that is my
particular area of expertise.

Ciarcia (Byte) had an atricle on building a cheap 1200 baud modem, you
might want to look at that.
-- 

      Eric Green {akgua,ut-sally}!usl!elg
        (Snail Mail P.O. Box 92191, Lafayette, LA 70509)

" In the beginning the Universe was created. This has made a lot of
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