Date: Wed, 16 Feb 2000 11:50:27 -0700 From: Brett Glass <brett@lariat.org> To: Terry Lambert <tlambert@primenet.com>, winter@jurai.net (Matthew N. Dodd) Cc: bright@wintelcom.net (Alfred Perlstein), brooks@one-eyed-alien.net (Brooks Davis), dscheidt@enteract.com (David Scheidt), troy@picus.com (Troy Settle), freebsd-chat@FreeBSD.ORG Subject: Re: Gimme FreeBSD anyday! Message-ID: <4.2.2.20000216114210.04307b30@localhost> In-Reply-To: <200002161837.LAA15588@usr02.primenet.com> References: <Pine.BSF.4.21.0002151229550.476-100000@sasami.jurai.net>
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At 11:37 AM 2/16/2000 , Terry Lambert wrote: >250ms of line silence, according to Technical Aspects of Data >Communication, McKneely, Digital Press, where in the appendices >they reproduce the Bell 103c and Bell 212 standards. The exact amount isn't part of any standard, unfortunately. My rule of thumb, when I wrote terminal emulation software, was that it should be a continuous "space" (zero) lasting approximately 10 character times at the current baud rate. It doesn't hurt any to make it too long, but if you make it too short some equipment doesn't pick it up. (It's an "out-of-band" signal, in a manner of speaking, since it's "illegal" in an asynchronous protocol to pin the line to a "space" for that long.) It's especially important to make your breaks good and long if you're using them for control purposes, e.g. a modem escape sequence. When Hayes started obnoxious enforcement of the Heatherington patent (which covered the +++<pause> escape sequence), some modem vendors used <BREAK>AT as an alternative. This choice was better than TIES (a time-independent escape sequence, where +++AT caused an immediate mode change) OR the Heatherington method, so I often set up systems to use it. --Bret To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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