Functional Description and Pinout
Pin #
31
Pin Name
Function
VCC
+5V ± 10ꢀ
39
DATA 1/
DATA 1/
Manchester Encoder Serial DATA Output (Max Load 40 pF).
38
Manchester Encoded Serial DATA Output (Max Load
40 pF).
29
33
T Inhibit
Transmit Inhibit Output (Max load 45 pF).
X
DATAST 1/
Manchester Encoded Serial DATA Output for purpose of
self-testing. Connected to decoder self-test input.
Controlled by Transmit/Self-Test function (max load 50
pF).
32
DATAST 1/
Manchester Encoded Serial DATA Output for Purpose Of
Self-Testing. Connected to Decoder Self-test Input.
Controlled By Transmit / Self-Test Function. (Max Load
50 pF).
41
20
40 MHz
40 MHz ± 0.1ꢀ TTL input to encoder. Symmetry 35ꢀ min.
Rise and fall times 5nSec max.
Parity Select
Low Level Input for even parity, high level input for odd
parity. Parity determined on 34 Bit word (Sync, W1, 32
Data Bits).
40
37
Encoder Enable
Asynchronous enable input pulse. Enables transmission
when a high level signal is input.
Transmit/ Self-Test
High level input enables transmission of data thru data and
data outputs: Disables DATA and DATA outputs; Which
st
st
both go to low logic state. Low level input enables
transmission of DATA thru DATA and DATA outputs;
st
st
Disables DATA and DATA outputs, which both go to high
logic state.
36
4 Bit SIS/SOS Select High level selects 4 Bit SIS/SOS transmission. This will
enable 4 Bit inputs to be loaded into the 4 Bit SIS/SOS
register
22
21
42
34 Bit Select
35 Bit Select
Sys Clr/Load
High level selects 34 Bit transmission (32 Data Bits, W1 Bit
and Sync Bit).
High level selects 35 Bit transmission (32 data Bits, W1 Bit,
Sync Bit and Parity Bit).
A low level allows data at input pins to be loaded, clears the
parity generator and initializes the internal controller. A
positive going edge latches input data present at that time
into the data registers.
6
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