Yaesu FT-767GX Operating Manual Download Page 36

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4. 1 8

CAT System Computer Control

The CAT ( Computer-Aided Tuning ) System in the
FT-767GX allows control of VFO/memory data

e n t r y, s e l e c tio n a n d t u ni ng ; I F s hi f t a n d

CTC SS tone selection by the operator' s exter

n a l perso n a l co m p u t e r.

Bi - directio n a l s e ri a l

d a t a i s p a s s e d vi a t h e CAT j a ck on t h e r e a r
panel of t h e t r a n sceive r, in the fo r m a t b e lo w :

DATA RATE : 4 800 bit s/sec
START BIT:

DATA BITS : 8
STOP BITS :

PAR ITY :

no ne

The chart at the bo ttom of this page shows the

entire  d a t a   s e q u e n c e   fo r  one  CAT  co m m and.
D a t a   is  t r a n s mi t t e d   fro m   left  to  rig h t,  so,
for  example,  Parameter  ( Parm )

of the Com m and

B lock is s e n t fir s t.

' S I ' ( S eri a l I np u t ) and

' S O '   ( S eria l   O u t pu t )  are  the  seri a l   data  bus
lines  a t   pins  3  a n d   2,  respectiv e l y,  on  t h e
CAT  jack.

No t e :

A l l d a t a b locks s e n t to t h e 767

m us t be five b y t e s lo ng.

The I nstruction Code sent by the external com
puter at the end o f each 5-byte Com m and Block

is the 'opco d e ' t h a t i n s t r u c t s t h e FT -767GX

w h a t actio n is to b e p e r fo r m ed. The I ns t r u c

tion C o d e C h a r t o n t h e nex t p age d e s c ri b e s
each valid I nstruction Code.

No tice t h a t mos t I ns t r u c tio n s require f ew o r

no arguments in the Parameter Bytes.

However,

every Com m and Block sent to the 767 must a l
w ays co nsist o f fiv e b y t e s.

The u n u s e d p a r

a m e t e r b y t e s wi l l b e i g no r e d when such I n
s t ru c tion s are exe c u t ed,

so their v a l u e is

irrelevant ( t hey need no t b e z ero ed ) .

A f t e r t h e co m p u t e r s e n d s t h e first C o m m an d

Block  the  767  should  echo  the  same  Block  back
to  the  co m pu t e r   ( wi t h i n   5  to  20m s ),  a l l ow i n g
your  com puter  software  to  check  that  the  Block
w a s   received  pro p e r l y,  ( i f   erro r   check i n g   i s
desired ) .

I f the echoed block does not m atch,

an  e r ror  h a s   occu r r e d   i n   t h e   s e r i a l   i n t e r f a c e,
and  the  Com m and  Block  must  be  resent  unt i l   the
echo  fro m   the  767  m a t ch e s   ( your  so f tw a r e
shou l d   ti m e   o u t   a n d   p roc e s s   t h e   error  a f t e r
t h r e e   t ries ) .

When the echo from the 767 m atches the Com m and

Block, the com puter next sends the 5-byte A CK
Block, which is m e r e l y fou r dum my p a r a m e t e r

b y t e s   a n d   a  speci a l   I n s t r u c tio n  Code  ( O Bh ) ,
w hich  i s   no t  echoed.  The r e   i s   no  ti m e   li mit
between  the  return  of  the  echo  by  the  767  and

sending of the A CK Block by your computer.

Upon receiving the A CK Block, the 767 proces

ses  the  com mand,  and  responds  on  the  CAT  SO
line  ( within  5  to  20ms )   with  the  Status  Update
d a t a,  which  is  eit h e r   5,  8,  26  or  86  b y t e s
lo ng,  according  to  t h e   o rigi n a l   I ns t r u c tio n

Code ( see the following C h arts and Tables ) .

CAT SYSTEM TIMING C HART

Data Byte

5 - bvte C o m m and

Block

TART

B I T

D O

Parrr1 4

( L S D )

D I

Parm 3