[Ham-Mac] Mac - SignaLink - CocoaModem

[Alan Bomberger]

Ok,  I guess I thought that sound cards contained A2D and D2A converters.
I guess this USB sound "adapter" just gets the signals onto the
USB bus and the Digital/Analog stuff is done in software.   I can
live with that.  Still doens't quite explain why the input signal
level is considerably higher with the power on..

Thanks for the info!!


>On Jun 19, 2012, at 2:33 PM, Alan Bomberger wrote:
>
>>  How is it that CocoaModem (and fldigi) can read signals from the
>>  SignaLink when the Signalink power is off?   I noticed this the
>>  other day when I went to answer a CQ and the transmitter didn't go
>>  on.  No Power, No PTT.  Granted the receiver input is much lower than
>>  with power on but what is running the ADC chip?
>>  --
>>  It is seldom that liberty of any kind is lost all at once. - David Hume
>>  <http://www.waldenpond.com/Thinker> Hypertext editor for creative people.
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>
>I am quoting from memory but as I recall the only active (or 
>powered) circuit in the SignaLink is for the Auto-PTT.  It is almost 
>passive for RX; however, when I had one I noticed some minor Rx 
>attenuation and this was confirmed by Tigertronics.
>
>Dick AA5VU
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-- 
It is seldom that liberty of any kind is lost all at once. - David Hume
<http://www.waldenpond.com/Thinker> Hypertext editor for creative people.