Quatech DS-3000, User Manual

Page: 23 / 27

O U T P U T C O N F I G U R A T I O N S
The other function of J2 and J3 is to configure the
c o m m u n i c a t i o n c h a n n e l i n h a l f o r f u l l d u p l e x m o d e . H a l f
d u p l e x o p e r a t i o n i s a c h i e v e d b y c o n n e c t i n g p i n s 4 a n d 8
o f t h e j u m p e r b l o c k ( f i g u r e 2 3 ) . T h i s a l l o w s t h e
t r a n s m i t t e r t o b e e n a b l e d a n d d i s a b l e d u s i n g t h e d a t a
t e r m i n a l r e a d y ( D T R ) o u t p u t i n t h e m o d e m c o n t r o l
r e g i s t e r . F u l l d u p l e x o p e r a t i o n i s r e s t o r e d b y r e m o v i n g
the jumper on pins 4 and 8 (figures 21 and 22).
Jumper J4 selects the level of DTR that enables the
t r a n s m i t t e r o u t p u t s . W h e n t h e e n a b l e c o n t r o l l i n e i s
c o n n e c t e d t o + D T R ( f a c t o r y c o n f i g u r a t i o n ) , w r i t i n g a
l o g i c 1 t o t h e D T R b i t l o c a t i o n i n t h e M O D E M c o n t r o l
r e g i s t e r e n a b l e s t r a n s m i s s i o n . W r i t i n g a l o g i c 0
d i s a b l e s t r a n s m i s s i o n . I n t h i s c o n f i g u r a t i o n , t r a n s -
mission is disabled on power-up.
Enable1
-DTR --+ | +-- +DTR
+-----------+
4 | o o--o | 6
J4 1 | o o--o | 3
+-----------+
-DTR --+ | +-- +DTR
Enable2
T o m a i n t a i n c o m p a t i b i l i t y w i t h s o m e o t h e r Q u a t e c h
p r o d u c t s , t h e e n a b l e c o n t r o l l i n e c a n b e c o n n e c t e d t o -
DTR. In this configuration, writing a logic 0 to the DTR
b i t l o c a t i o n i n t h e M O D E M c o n t r o l r e g i s t e r e n a b l e s
t r a n s m i s s i o n , l o g i c 1 d i s a b l e s t r a n s m i s s i o n . I n t h i s
configuration, transmission is enabled on power-up.
Enable1
-DTR --+ | +-- +DTR
+-----------+
4 | o--o o | 6
J4 1 | o--o o | 3
+-----------+
-DTR --+ | +-- +DTR
Enable2
C A U T I O N :
W h e n o p e r a t i n g i n h a l f d u p l e x m o d e , t h e
t r a n s m i t t e r m u s t b e d i s a b l e d b e f o r e r e c e i v i n g
a n y i n f o r m a t i o n . F a i l u r e t o d o s o w i l l r e s u l t
i n t w o o u t p u t d r i v e r s b e i n g c o n n e c t e d t o g e t h e r
w h i c h m a y c a u s e d a m a g e t o t h e D S - 2 0 0 0 , t h e
computer and the peripheral equipment.
iii