Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: Suitable serial card for H/S modem
Message-ID: <3801.27c53c7e@hayes.uucp>
Date: 22 Feb 91 15:45:02 GMT
References: <3787.27c196cc@hayes.uucp> <6553@khaki8.UUCP> <12646@darkstar.ucsc.edu>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 22

In article <12646@darkstar.ucsc.edu>, goat@ucscb.UCSC.EDU (Craig
Stephen Campbell) writes: 

>  the hayes ESP may be a great product, but at $250 list i'll get a 
> $25 dollar I/O card and a $13.00 NS16550AFN and call it a day.

And if that solves your problem, that's what you should do!  But 
since the 16550A by itself does not provide automatic flow control 
if its receive FIFO starts to fill up, you can still lose data if 
you main CPU can't give its attention at least once ever 16 
character times.  And since it can't do DMA transfers (and even with 
the FIFO, still requires CPU attention at least once every 16 
characters), you still have a significant impact on foreground tasks 
if you're communicating at high speed in the background.  

We never said ESP was for everybody, but if you need it, it's there!

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net