The Signalink doesn't require a separate line from the PC to the interface for
PTT. Instead, it has its own VOX circuitry to key the transmitter when it
hears data from the PC.
Some people really prefer this. I happen to prefer having the PC program
(HRD's DM780 in my case) directly control PTT. My main pc has a spare serial
port that I use for this purpose, but I've also used it on my laptop with a USB
to serial adapter.
It's really easy to build just a serial PTT circuit from a few cheap parts. If
I used the Signalink USB, I'd do that and not use its VOX. Or, you can get an
interface that expects the PTT line froom the PC and drives the radio's PTT
pin.
In my case, I'm using a Buxcomm Rascal as the interface. It doesn't have a
built-in soundcard like the Signalink USB, so I have used a US $10 soundcard
that I added to my tower PC, and right now I'm using an external USB sound
device (both the Creative USB Soundblaster and the Creative Audigy NX at
different times). It's a little more hardware than the Signalink approach, but
I get my PC-driven PTT.
I have also played with the very inexpensive USB sound FOBs you can get on eBay
for almost free.
But, as I say, some people really prefer the VOX PTT. So we all have choices.
Jim - K6JM
----- Original Message -----
From: Raymond Lunsford
To: digitalradio@yahoogroups.com
Sent: Wednesday, August 11, 2010 3:01 PM
Subject: Re: [digitalradio] Good USB sound card ?
Yes,use Signalink USB.I've got one works great,K4YDI.
On Wed, Aug 11, 2010 at 3:04 PM, graham787 <g0...@hotmail.com> wrote:
Looks like the RDX-150-EF has been dropped
any ideas on a 'good' usb card for data use ??
Tnx - G.
