Ian Bell wrote:
> On Wednesday 24 Sep 2003 4:17 pm, you wrote:
>> How do they get away with this?
>>
>> They have an RS232 line going into a digital I/O port using just a
>> couple of resistors.
>>
>> Also, the 7404 as a line driver. How much cable and speed is that
>> good for?
>>
>
> That's bloody criminal.  Note they have two 7404s in parallel.

Naw, it's called 'letrical injunearing.  Their circuit will work fine in
probably >90% of the applications.  I'm sure that HEX inverter costs
allot less than a MAX232, plus it doesn't need four expensive
electrolytic caps.  It probably saves more than a US$1.00 per unit.
Although I do wonder why they didn't use the other three inverters,
maybe they're spares for when you kill the first three.  ;-)

michael brown

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