Phone line interface for DTMF

Hi all,

I would use a 600 ohms phone line transformer
to have dc isolation, for transmitting DTMF from
a computer.

My very simple desing work at home, but
doesnt work at the office. It seams I don't
deliver enough audio level of DTMF.

Earlier, I bought a very simple "play/record"
device who did work (more audio DTMF level),
but humming soon happen with differents
configuration.... (not use transformer in)
It is probalby caused by different ground
voltage level, between computer and Telco gnd.

Is someone out there, can rely me to some pretty
schematics on the web, or have any suggest
to do it right?

jmarc...

Relevant Pages

  • Re: Phone line interface for DTMF
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    (sci.electronics.design)
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  • Re: Phone line interface for DTMF
    ... jmarc wrote: ... I would use a 600 ohms phone line transformer ... deliver enough audio level of DTMF. ...
    (sci.electronics.design)
  • Re: Phone line interface for DTMF
    ... I already thought using a modem. ... I would use a 600 ohms phone line transformer ... deliver enough audio level of DTMF. ...
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  • Re: Phone line interface for DTMF
    ... I would use a 600 ohms phone line transformer ... deliver enough audio level of DTMF. ...
    (sci.electronics.design)