ESI VideoBridge 2150, Service Manual

Page: 155 / 332

2 . 9 . 7 Program Wr i te-Protec t
I mpo r t a n t pa rame t e r programs can be p r o t e c te d f rom a c c i de n t a l e ra s u re
w i t h t h e ca s s e t t e w r i t e -p r o t e c t f e a t u re , of w h i c h t he r e a re tw o type s .
One type f e a t u r e s a sw i ve l p l u g l oc a t e d a t t h e t op o f ea c h s i de o f the
c a s s e t te mod u l e ( F i g u r e 2 - 2 0 ) . To pr o t e c t r e c o r d e d p r o g ra m s on S i d e A
( w h i c h f a c e s t he ope r a t o r upon i n s e r t i on ) f r om b e i ng o v e rw r i t t e n ,
p i vo t t h e p l ug on S i de B 1 /2 t u r n c l o c kw i se t o u n c o v e r t h e re c ta n g u l a r
h o l e be ne a t h i t . S i m i l a r l y , t o pr o t e c t S i de B , p i v o t t he p l u g o n S i de
A . W i t h t h e plug in t h i s p o s i t i on , no a dd i t i on a l d a ta c a n be w r i t te n
o v e r t h e e x i s t i n g p r o g r a m s o n t h e o p p o s i t e s i d e o f t h e t a p e w i t h
re spe c t t o t h e p l u g . To r e s tore t h e tape t o i t s u np r o t e c t e d s ta te ,
s i mp l y p i vo t t h e p l ug c o u n t e r c l oc kw i se ba c k to i t s o r i g i na l po s i t i o n .
C a s s e t t e s w i t h t h e o t h e r type o f w r i t e - p r o t e c t f e a t u re have a
c r o s s - s h a p e d p l u g l o c a t e d o n t h e t o p o f e a c h s i d e o f t h e m o d u l e
( F i g u re 2 - 2 0 ) . T o p r o t e c t t h e se c a s s e t t e s f rom b e i ng o v e rw r i t t e n ,
p u s h ou t t he c r o s s- s ha p e d p l u g . W i t h t he p l u g on S i de B remove d , n o
a d d i t i on a l d a t a c a n be w r i t t e n o v e r t he e x i s t i n g p r o g ra m s on s i de A .
To pr o t e c t S i de B , p u s h o u t t he p l ug o n S i de A . Ca s se t t e s w i t h t h e
w r i t e - p r o t e c t p l u g r e m o v e d c a n be reprog rammed by p l a c i n g a p i e c e o f
c e l l op ha ne t a p e ove r t he w r i te-pro t e c t h o l e .
SW I V E L PLU G PUSH - OUT P L U G
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F i gure 2 - 2 0 . Swi ve l and Pus h-Ou t Wri te-Prote c t Fea tures
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