To: Gene Heskett <gene.heskett@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, David Newall <davidn@davidnewall.com>,
       Greg KH <greg@kroah.com>, linux-usb@vger.kernel.org,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Handshaking on USB serial devices
References: <47B30291.2040905@davidnewall.com>
	<47B40918.20206@davidnewall.com> <20080214121026.16a9c510@core>
	<200802141116.14722.gene.heskett@gmail.com>
From: Krzysztof Halasa <khc@pm.waw.pl>
Date: Thu, 14 Feb 2008 23:39:09 +0100
In-Reply-To: <200802141116.14722.gene.heskett@gmail.com> (Gene Heskett's message of "Thu\, 14 Feb 2008 11\:16\:14 -0500")
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Gene Heskett <gene.heskett@gmail.com> writes:

> Apparently they do not Alan, the pl2303 in particular is a problem child, 
> throwing several lost com errors a day when doing nothing more strenuous than 
> talking to my belkin UPS from apcupsd, very small packets there, 20 bytes I 
> believe at several second intervals.

Is your UPS using "modern" hardware handshaking (CTS = PC can send,
with RTS practically always asserted)? Or perhaps the "old",
"half-duplex" V.24-style (RTS asserted before TX and then waiting for
CTS)?

Are you sure it uses hw handshaking at all? Most (all?) UPSes I used
had only TxD and RxD (for RS-232).
-- 
Krzysztof Halasa
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