Before this gets out of hand...

A) Both sides of this argument have valid and useful points.

B) Making unprovable assertions or asking for un-produceable standards is
not going to help anybody get work done.

Let us not focus on the war, but rather on the results. Having said that, I
am impressed that everyone has kept calm and non-personal so far. If it gets
out of hand, I probably won't have time to do more than just unsubscribe the
people who are shouting.

Can we just leave it at...
A) TTL RS232 does NOT adhere to the standard and is probably not acceptable
in a professional, high reliability design.

B) TTL RS232 is a lot less expensive and easier than full signal conversion,
will PROBABLY work just fine, and may be justified for hobby or low cost,
high volume designs. But if you can spare a penny or two...
http://www.piclist.com/techref/io/serial/ttl-rs232.htm
Has a bunch of nice little tricks for converting ttl to and from rs232
without the expensive MAX232 chips, et all...

---
James Newton, Admin #3 mailto:jamesnewton@piclist.com
1-619-652-0593 VM 1-208-279-8767 FAX
PIC/PICList FAQ: http://www.piclist.com or .org

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Olin Lathrop
Sent: Monday, September 10, 2001 04:35
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]:Simple RS232 hardware


> I explicitly qualified my comment as
> applying only to PCs, which will always use one of a few standard
> transceiver chips, not any special 'high noise immunity' one,

So I suppose you can show us the official specification for a PC that says
the COM port receive levels shalt be 5V logic compatible?


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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