Sorry...I should have realized that the ST-1 interface is completely different than the ST-2 Omni interface. (I started last summer with an ST-1, then moved up to the ST-2) In any case, try the following:
Hold power and + for 3 sec brings up code0000 set it 0003 this returns 0 or 1
Hold power for 3 sec to save
I found this from researching the Forum and copied it from member Optimax...