Service 
Model 
8901B 
%ble 
8A-6. 
Schematic Diagram Notes 
(4 
of 
11) 
9p 
.c 
+ 
4 
3- 
DIGITAL 
SYMBOLOGY 
REFERENCE  INFORMATION 
Input  and  Output  Indicators 
Implied Indicator-Absence 
of 
polarity indicator (see below) implies that the active 
state is a relative high voltage level. Absence of negation indicator (see below) im- 
plies that  the active State is a  relative high voltage level at the input or output. 
Polarity Indicator-The  active state is a relatively low voltage level. 
Dynamic Indicator-The  active state is a transition from a relative low to a relative 
high voltage level. 
Inhibit Input-Input  that, when active, inhibits (blocks) the active state outputs of a 
digital device. 
Analog Input-Input  that  is a continuous signal function (e.g.,  a sine wave). 
Polarity Indicator used with  Inhibit Indicator-Indicates  that the relatively low level 
signal inhibits (blocks) the active state outputs of a digital device. 
Output Delay-Binary  output changes state only after the referenced input 
(rn) 
re- 
turns to its inactive state 
(rn 
should be replaced by appropriate dependency or func- 
tion symbols). 
Open Collector Output. 
Open Emitter Output. 
Three-state Output-Indicates  outputs can have a high impedance (disconnect) state 
in 
addition to the normal binary logic states. 
8A-13