Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!hsi!stpstn!lerman
From: lerman@stpstn.UUCP (Ken Lerman)
Newsgroups: comp.sys.next
Subject: Re: RS423 - RS232 line levels (volts) different
Message-ID: <5972@stpstn.UUCP>
Date: 31 Dec 90 15:41:12 GMT
References: <qce1u1w163w@questor.wimsey.bc.ca>
Reply-To: lerman@stpstn.UUCP (Ken Lerman)
Organization: The Stepstone Corporation, Sandy Hook, CT 06482
Lines: 31

In article <qce1u1w163w@questor.wimsey.bc.ca. lclarke@questor.wimsey.bc.ca (Lawrence Clarke) writes:
.The Network Administrator's guide tells you how to convert a from the new
.NeXTstation's RS423 serial port to an RS232 port. But they forgot to 
.mention that the RS423 uses +- 5 volts and an RS232 uses +- 12 volts.
.I have some equipment that was built to RS232 specs and will not work with
.the NeXTstation. Some of the newer modem's out there will work though, as
.most of them were not built to RS232 specs. There's more than just a pinout
.difference between the 2 standards (RS423 - RS232).
. 
.USER'S BEWARE !!!
.
.
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My recollection is that RS232 requires the source of a signal to
generate from plus or minus six volts to plus or minus twenty-five
volts.  (Plus for a mark and minus for a space, I think.)

The receiver of an RS232 signal must be capable of receiving from plus
three to plus thirty (I think) and from minus three to minus thirty.

Thus, a signal of +-5 volts does not meet RS232 specs, but if it is
connected to a conforming receiver, it should work fine.

Ken