Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/3/84; site sesame.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!sesame!slerner
From: slerner@sesame.UUCP (Simcha-Yitzchak Lerner)
Newsgroups: net.micro.pc
Subject: Re: Does DOS listen to LaserJets?
Message-ID: <272@sesame.UUCP>
Date: Wed, 14-Aug-85 19:39:59 EDT
Article-I.D.: sesame.272
Posted: Wed Aug 14 19:39:59 1985
Date-Received: Mon, 19-Aug-85 07:20:37 EDT
References: <596@alberta.UUCP> <13600015@hp-pcd.UUCP>
Organization: Lotus Development Corp
Lines: 29

> 
>  This must be a case of software inertia in action. Actually I think the "few
> chars" that are sent is caused by using a double buffered UART with software
> testing of the DTR status...... 
> 
>   Many UARTS avoid this problem by providing a hardware holdoff input pin
> (normally the CTS* input). These UARTs would test the pin before sending a
> start bit and in the above case would pause before sending character N+2.
> Character N+1 would be stored in the receiver's input buffer until read
> so nothing would be lost.
> 
> John Eaton
> !hplabs!hp-pcd!john

The only proble with CTS is that not all machines wire it thru.  The
reason for this is that there are a lot of UARTS out there with a bad
bug:  if CTS transitions mid-character xmision, the character is trashed.


-- 
Opinions expressed are public domain, and do not belong to Lotus
Development Corp.
----------------------------------------------------------------

Simcha-Yitzchak Lerner

              {genrad|ihnp4|ima}!wjh12!talcott!sesame!slerner
                      {cbosgd|harvard}!talcott!sesame!slerner
                                slerner%sesame@harvard.ARPA