[Ham-Mac] Digital Interface for PSK with PTT

[Dick Kriss]

John,

My primary reason for selecting the SignaLink SL-1+ interface was the unique
Auto-PTT feature.   How do you handle the PTT on the rig with the home brew
interface? Surely your no using VOX for xmit.

73, Dick AA5VU


On 6/19/06 5:04 PM, "John Townend" <jltownend at btinternet.com> wrote:

> Larry Coyle, K1QW, has an excellent article entitled "An Improved
> Digital Communication Interface" in this issue.  With two 600 ohm 1:1
> line transformers, a quad op-amp, a meter and a handful of components a
> reliable and flexible interface can be made.  Like Larry I used perf
> board and - surprise - it worked first time.  Coupled from the iMic it
> provides reliable switching of the PTT line, gives DC isolation of the
> rig from the computer and the preset potentiometers allow the input and
> output levels to be set.  The audio level indicator section is a handy
> add-on and could be constructed on its own with a single op-amp and
> used as an audio level probe.
> 
> All in all it's a useful and versatile piece of gear to have around
> and, if you're handy with the soldering iron, an alternative to
> commercial units such as  SignaLink.    CU on PSK..................73
> John G3BBD / N3YZR