OUTPUT CONFIGURATIONS
VIII. O U T P U T C O N F I G U R A T I O N S
T h e f u n c t i o n o f j u m p e r J 2 i s t o c o n f i g u r e t h e
communication channels in half or full duplex mode. Half
duplex operation is achieved by installing a jumper block
over the pins for the specific channel (figure 21). This
c o n n e c t i o n 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
disabled using the data terminal ready (DTR) output which
i s c o n t r o l l e d t h r o u g h t h e m o d e m c o n t r o l r e g i s t e r o f t h e
1 6 4 5 0 / 1 6 5 5 0 . W h e n D T R i s s e t ( l o g i c 1 ) , t h e t r a n s m i t t e r
d r i v e r i s e n a b l e d f o r o u t p u t o n t h e c h a n n e l . W h e n
c l e a r e d , ( l o g i c 0 ) , t h e t r a n s m i t t e r o u t p u t e n t e r s a h i g h
i m p e d a n c e s t a t e . 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
removing the associated jumper.
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
any information. Failure to do so may result
i n m u l t i p l e 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 Q S -
2 0 0 M / Q S - 3 0 0 M , t h e c o m p u t e r a n d t h e p e r i p h e r a l
equipment.
+---------- Output enable 1
| +------- Output enable 2
| | +---- Output enable 3
| | | +- Output enable 4
+--------------+
5 | _ _ _ _ | 8
1 | _ _ _ _ | 4
J 2
+--------------+
DTR 1 -+ | | |
DTR 2 ----+ | |
DTR 3 -------+ |
DTR 4 ----------+
Figure 21. Half duplex jumper configuration.
