[aprssig] ICOM 706 Data Out (disc)

Ray Wells vk2tv at exemail.com.au
Fri Jul 20 02:43:56 EDT 2007

Stephen H. Smith wrote:

> Andrew Rich wrote:
>> Gudday
>> I see a port on the back of the ICOM 706 MKii G is marked for packet use.
>> It provides 1200 and 9600 baud connection points.
>> Would I be right in saying that the 9600 baud stage by passes the 
>> audio stage and is what they call a disc out ?
> Yes.    The "1200 Baud out" is audio the same as at the speaker 
> (except that the level is fixed) and is live on all modes (CW, SSB, 
> AM, FM, etc).  On FM this output is usually de-emphasized and 
> squelched.   

Mmmm, reminds me of getting caught out years ago when, for convenience 
at the time, I used the speaker audio to drive a 1200bps TNC. It would 
decode just the occasional packet. Turned out that the rx audio to the 
speaker was severely sloped, presumeably to make the radio less tinny, 
and the 2200Hz tone was some 8dB down on the 1200Hz tone. I ended up 
installing an emitter follower to pick up constant-level, flat audio 
from the top of the volume control. Problem fixed! The radio is an FDK 

Ray vk2tv

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