Honeywell SPZ-8000 - RS-422 Synchronous; SG-884 Symbol Generator (SG) ASCB Inputs

4. B.
(1) (a) S
I
I
~
SG-884 Symbol Generator (SG) ASCB Inputs
The NZ-920 inputs left, right, and center SG data. It
processes and uses data from all three SGS when available
and valid.
The NZ-920 determines SG reversionary or backup modes (WSP
1) from the SG and processes the appropriate SG data based
on this reversion data.
DA-884 Data Acquisition Unit (DAU) ASCB Inputs
The NZ-920 inputs all four DAU transmissions (1A, lB, 2A,
2B) . It processes and uses the DAU data as selected by its
on-side display controller.
If the selected DAU is invalid,
the NZ-920 switches and uses data from its corresponding
secondary channel (i.e., 1A or lB, 2A or 2B).
If the
selected DAU channel becomes
valid, the NZ-920 switches and
uses the selected channel.
DC-884 Display Controller (DC) ASCB
Inputs
The NZ-920 inputs and processes on-side display controller
data.
FC-880 Fault Warning Computer (FWC) ASCB Inputs
The NZ-920 inputs both left and right FWC data.
(b) NZ-920 Navigation Computer ASCB Outputs
The NZ-920 transmits two types of data onto the
ASCB; basic
data and background data.
(2) RS-422 Synchronous Interface
This RS-422 interface is a synchronous serial digital data bus.
Data is transmitted over a shielded twisted pair cable. The
implementation of the RS-422 in the navigation computer has the
following parameters:
. SDLC
● CRC ITT
. No
parity
● 312.5k baud
All data is transmitted in a byte format using eleven-bit groups.
Each group consists of a start bit, followed by 8 data bits,
followed by a parity bit (odd), and ending with a stop bit. The
data is transmitted least significant bit first on the bus.
22-14-00
Page 298.156
Apr 15/93
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