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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.micro
Subject: Re: RS-232
Message-ID: <5831@utzoo.UUCP>
Date: Fri, 26-Jul-85 13:09:19 EDT
Article-I.D.: utzoo.5831
Posted: Fri Jul 26 13:09:19 1985
Date-Received: Fri, 26-Jul-85 13:09:19 EDT
References: <157@brl-tgr.ARPA>
Organization: U of Toronto Zoology
Lines: 10

> One side comment is that the ranges for RS-232 are actually 3-25.

Yes and no.  RS232B, which is obsolete, specified +-25 as the upper
limit of transmitter output voltages.  RS232C, the modern standard,
specifies +-15 as the maximum transmitter output (whence the +-15
limit on the 1488 transmitter chips).  However, the receivers still
have to be capable of withstanding +-25, for compatibility.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry