Date: Mon, 28 Oct 2002 10:05:39 -0600 (CST) From: Chris Dillon <cdillon@wolves.k12.mo.us> To: Soeren Schmidt <sos@spider.deepcore.dk> Cc: Ronald G Minnich <rminnich@lanl.gov>, <"."@babolo.ru>, David Nicholas Kayal <davek@saturn5.com>, <freebsd-chat@FreeBSD.ORG> Subject: Re: Show me the light Message-ID: <20021028094516.I34529-100000@duey.wolves.k12.mo.us> In-Reply-To: <200210272253.g9RMrs2G024315@spider.deepcore.dk>
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Sending this one to -chat, since we're waxing nostalgic now... On Sun, 27 Oct 2002, Soeren Schmidt wrote: > Only the control signals are OC, the databits are tri state. > Actually, depending on how many databits one needs, the rest can be > used to provide a usable powersupply when they are set to '1'. I > use that for an 8chan AD converter that then fit into the parport > plug housing and no need for an external power supply. But beware > the current you can get this way is very limitted... Heh. Back when I had an 8086 XT and liked to listen to MODs and similar tracked music types, I built a very simple diode ladder DA converter that used the 8 output bits of the parallel port (9 output levels, so just slightly better than 3-bit resolution). Since it just used a few discrete diodes and resistors, it all fit inside the cover of the plug and had nothing but an RCA pigtail coming out of it that you could hook up to an amplifier. It at least sounded a LOT better than trying to get the output from the PC speaker. :-) Obviously we're talking millivolt signals here and it didn't need to pull more current than was required to drive the pre-amp of whatever amplifier you hooked it up to. -- Chris Dillon - cdillon(at)wolves.k12.mo.us FreeBSD: The fastest and most stable server OS on the planet - Available for IA32 (Intel x86) and Alpha architectures - IA64, PowerPC, UltraSPARC, ARM, and S/390 under development - http://www.freebsd.org No trees were harmed in the composition of this message, although some electrons were mildly inconvenienced. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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