Re: Alternative circuit for caller ID converter?

["Patrick Lidstone" <patrick@xxxxxxxxxxxx>]

--- In ukha_d@xxxxxxx, Stuart Grimshaw <stuart@s...> wrote:
> Maxim have the following datasheet for http://pdfserv.maxim-
ic.com/en/ds/MAX250-MAX251.pdf
>
> Does figure3 look like a circuit that could be used instead of the
one described on Jon Payne's website?
>

You don't really need the optoisolated element of this solution. Look
for a MAX232 data sheet instead.

> My idea is to try and grab the serial data as it's sent to an
existing LCD, much like the CLID, but instead this is a vending
machine, I'm fed up trapesing all the way downstairs only to find out
it's out of coffe/cups/change
>

Are you sure the data is sent to existing LCD on a serial basis - it
would be a bit surprising if it was. The caller id hack doesn't
intercept LCD data, it intercepts what is effectively the modem data
stream that is the CID data.

You'll probably hate me for saying this, but I reckon you'd be better
off with an axis-type wireless webcam, zoomed in on the panel. Plus,
then you can also see if there is a queue :-)

Patrick



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