[GreenKeys] Current Loop to RS-232 Conversion on ASR33

[Rob Jarratt]

> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-
> bounces at mailman.qth.net] On Behalf Of epvgk at limpoc.com
> Sent: 25 March 2013 00:33
> To: r.jarratt at computer.org
> Cc: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] Current Loop to RS-232 Conversion on ASR33
> 
> On Sun, Mar 24, 2013 at 11:44:04PM -0000, Rob Jarratt wrote:
> > Yes, I think what you say may be right (although mine does not have a
> > telephone panel). But even if you are right and it does have a loop
> > supply inside the ASR33 why does it only appear to output about 10mA
> > and then drop to the point that it starts to chatter as if it was
> > open? Yet, when in local mode it works perfectly, so the current would
> *appear* to be enough.
> >
> 
> It's also worth considering that if you did at some point connect more
than
> one highish-voltage supply into the loop in series, you may have damaged
> either the current loop converter or the tty's solenoid driver?
> 
> eric


Yes, this is something that worries me now that I see that the TTY seems to
be sending current. I am not sure how to test for such damage though.

Regards

Rob