[time-nuts] RS-232 Standard

Mike Feher mfeher at eozinc.com
Sun May 23 01:58:45 UTC 2010

Yes, there is a standard and I have an original copy. It is an EIA standard
for 422A, 423A, 232C, & 449. It was published in 1984. Some of the actual
standards within the large document go back to the early 70's. Regards -

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Robert Darlington
Sent: Saturday, May 22, 2010 9:47 PM
To: didier at cox.net; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)

Was there ever a standard?  I always thought the "RS" stood for
Recommended Standard, as in "you *should* do the following" as
compared to "you shall do the following"  I've seen inverted TTL talk
to the RS232 port on laptops and I even sometimes use the max233's
(+/- 10 volts instead of 12), but always use the full max232 with
external charge pumps when it's a gadget that needs to work everytime
with systems from multiple countries.


On Sat, May 22, 2010 at 7:21 PM, Didier Juges <didier at cox.net> wrote:
> Bruce,
> Thanks for the additional information.
> +/- 14V is quite unusually low in my experience. I typically use Maxim
parts such as the MAX220 series, which is specified at +/-25V for no damage
on the inputs (some parts in that series go to +/-30V).
> The bottom line is that as I pointed out earlier, there is no such thing
as an RS-232 standard any more.
> Didier

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