[E3-hacking] Another hello

Andy andy at entropy.demon.co.uk
Wed Jan 18 20:21:26 GMT 2006

Hi Guys,

I've just joined this email list and have noticed some confusion from 
people on the E3's EXP serial port and getting an output from. There is 
confusing information out there on if  RS232 line drivers are needed, or 
not.. With the aid of an old scope I _think_ I now know what is going on 
and why some say no line driver is needed, but others say you do...

The short answer is what comes out is inverted,  like RS232, but is not 
at valid RS232 voltage levels as it never swings negative. Some PCs 
might let you get away with this, many wont. Being already inverted 
connecting this to typical RS232 line driver chip then re-inverts the 
signal and that wont work either.

I've thrown together a webpage on this here and my quick bodge solution.


I'll flesh this out a bit more when I get a chance.

Does anyone know of any good sites for "beginers" on hacking the E3 
emailer? I've mostly been using these two sites that are easy to find on 


But neither seems to help a relative "newbie" like me to get going quickly.

    Best regards,

          Andy M

David Given wrote:

>On Wednesday 18 January 2006 18:48, mark wrote:
>>As you say I forgot to mention that the model I have is an e3.
>Aha. Yes, it's only the E2 (and possibly the original eMailer) that need the 
>line level converter.
>e3-hacking mailing list
>e3-hacking at earth.li

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