Uart through an audio transformer

[TheM]

Hopefully, it's to timestamp, in a very primitive way an audio feed.
The idea is to just dump N81, from the uart at a low level, say -30
or-40dBFS, and then have a little black box containing a preamp to
logic levels to drive a FTDI 232/USB thing, or maybe a USB HID/
keyboard. I like the idea of using a cheapo telecom/modem transformer,
because it is floating, and will take up less PCB real estate than the
electronically balanced equivalent.
The Etal P3181 ( from farnell etc) seems to fit the requirements

I'll try it on my canon xl1s audio channels, to see if it works, when
I get my hands on a P3181

martin

A bit steep, but a nice no-hassle part. I wonder how it performs above 4KHz.

I was recently thinking about sending some data over audio channel, but
above audible range. Haven't quite figured out yet how to do it without
much hardware. FSK at 20+ KHz probably.

M

 

[Martin Griffith]

One question, is it a problem if your data stream is audible?

M

Not a problem, the data is only dumped when required. been mucking
around with some irritating 8051 bugs, so I havent really got any
further with this

martin