[ICOM] Computer Control Interface

[Jerry Flanders]

Comment: There are several different optos available, with different 
"gain". Just use one that has sufficient "gain". Also - slightly 
increasing current through its LED by slightly reducing the 
resistance of the current-limiting resistor also would help to insure 
if keying is marginal. Verify capability of your serial port line 
before you get wild with this.

Jerry W4UK

At 17:42 12/27/2005, Gary wrote:
>Bob,
>
>I was looking at the MFJ-1279 schematic and the CW out is using a 
>Opto Isolator. In the past I remember an Opto isolator not being 
>able to place a hard enough ground on the Icom UP / Down input.