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Path: utzoo!mnetor!seismo!ut-sally!husc6!harvard!bunny!mlr0
From: mlr0@bunny.UUCP (Martin Resnick)
Newsgroups: net.micro.mac
Subject: Re: DTR held high from program control?
Message-ID: <549@bunny.UUCP>
Date: Thu, 18-Sep-86 22:57:49 EDT
Article-I.D.: bunny.549
Posted: Thu Sep 18 22:57:49 1986
Date-Received: Sat, 20-Sep-86 00:09:57 EDT
References: <458@aecom.UUCP>
Distribution: net
Organization: GTE Laboratories, Waltham, MA.
Lines: 10

> Is it true that DTR will only go high if the communications program
> tells it to?  Does Red Ryder do this?  I am interested, because I want
> to be able to set up a Mac+ for *dialin* purposes, and I don't want the
> modem to answer unless the Mac is on and ready to talk.
> -- 

Opening the serial driver on the Mac+ automatically asserts DTR.
Closing the driver releases DTR.

There are also individual commands to assert/release DTR.