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From: porter@cbmvax.cbm.UUCP (Jeff Porter)
Newsgroups: net.micro.cbm
Subject: Re: 1670 modem
Message-ID: <759@cbmvax.cbmvax.cbm.UUCP>
Date: Mon, 22-Sep-86 00:07:37 EDT
Article-I.D.: cbmvax.759
Posted: Mon Sep 22 00:07:37 1986
Date-Received: Mon, 22-Sep-86 21:55:37 EDT
References: <784@mtund.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 35

> 	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 prog. manual gives a discription of the user port
> but some connections  are unassigned. Is there a book
> available which can give me a better discription of
> 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.
> 				Thanks alot,
> 				Steve M
> 				ihnp4!mtund!srm

The 1670 is a Hayes type modem, and hence the phone number
is transmitted to the modem via the TxD and RxD lines.
The Programmers Reference guide has a section on RS232
that should give you some info about what signals are what.
If the signals were not mentioned in the back of the 1670
manual, then they are not connected to the 1670.  Off-hook
is not available, neither is Speed Indicate, but Ring Indicate is.
Off hook and Speed Indicate are obviously available internally.
There is no standard place for these signals on the user port
however.  The back of the 1670 manual goes into how to detect
speed in software.  Your program should already be able to know
if it has told the 1670 to go off hook or not.

There are two 8049 microprocessors in the 1670 to interpret the
TxD and RxD data.  

Hope this helps,
Jeff Porter
Commodore Engineering