> Peter OZ1PIF/5Q2M wrote: > Either you have to add an external USB-> RS232 >[...] or resort to the VOX solution.
Hi Peter, For ARQ or handshaking modes, VOX is simply way too slow. Signalink will not work. Not an option. Let's crunch the numbers: 1. Really fast VOX with 25milliSecond PTT delay. 2. Add 12mSec to 30mSec transmitter 90% power ramp-up. 3. Total delay = 37mSec to 55mSec! Now, let's take a typical example of a slow ARQ or handshaking mode running at 125 baud (symbols/second) It transmits one symbol every 8 milliseconds. In 37mSec, you have missed 4 symbols. In 55mSec, you have missed 7 symbols. Each time you miss some symbols, this creates more errors that need to be corrected somehow. So, each transmission with a VOX system, you create errors... and each ARQ transmission is trying to fix the previous transmission's error, and the previous errors in the transmissions before that... a vicious cycle :) The other issue is VOX release delay. The longer it is, the more the receive decoder will miss symbols. VOX is totally wrong for ARQ modes. I'm surprised that Signalink doesn't offer any RTS keying, it would be so easy to add to their interface. They are really shooting themselves in the foot with their design choice. A lot of hams are buying these Signalink and other VOX interfaces, and they don't realize what they are missing by doing so. Of course, Signalink doesn't tell them, (the truth would be bad for business). 73 Bonnie VR2/KQ6XA .
