Cn-2548 Board; Rm-Br300 Circuit Description - Sony BRC-300 Service Manual

5-2-2. CN-2548 Board

The CN-2548 board is a connector board to connect the
optional cards BRBK series (except the BRBK-303).
Up to two different optional cards can be connected.
Through this board, camera image data output from the
demultiplexer, clock, communication data, and other
signals are sent or received to/from the optional boards.
An interface is provided to update the microcomputer
program. Such update is enabled with the specific board
connected to this board.
BRC-300/300P
BRU-300/300P

5-3. RM-BR300 Circuit Description

The RM-BR300 consists of MD-131 board, SW-1205
board and a joystick.
The MD-131 board comprises a control microcomputer,
three external I/O connectors, and a power supply circuit.
The SW-1205 board comprises three operation rotary
encoders, switches and indicator LEDs.
The RM-BR300 is configured with a parallel connection of
the joystick, rotary encoders, switches, and the LEDs on
the operation panel to the microcomputer.
The microcomputer memorizes the state of the joystick,
rotary encoders and switches, and sends/receives com-
mands and status data to/from external unit using the
VISCA protocol.
IC5009 and IC5011 on the MD-131 board are transceivers
operating on the VISCA protocol. IC5009 is provided for
the RS-232C interface, and IC5011 for the RS-422 inter-
face.
Selection of RS-232C or RS-422 and selection of baud rate
(9600 or 38400 bps) are set by the DIP switch S5003, and
are input to the microcomputer. These selections are also
provided for BRC-300/300P and BRU-300/300P. Both
selections shall be the same in all these three units.
The microcomputer makes the LEDs on the operation
panel display remote-control result data.
The RM-BR300 has contact output signals (make/break) to
control an external camera switcher, and tally input signals
(make/break) to receive control from an external camera
switcher.
These contact output signals and tally input signals are
output or input through the connector CN5008. The
microcomputer reads the setting of the TALLY/CON-
TACT switch S5004, and the selectors IC5014, IC5015,
IC5019, and IC5020 switch between input and output
signals.
The open-collector driver IC5018 connects/disconnects the
contact output with control pulses from the microcomput-
er.
Regarding the tally input signals, the microcomputer
recognizes make/break ports to control the camera selec-
tion of RM-BR300.
EEPROM IC5010 saves microcomputer data that must be
retained even during power OFF.
The +12 V given to the DC IN jack is fed to the series
regulators through the ON/OFF switch on the rear panel.
The series regulators generate +5 V DC and +3.3 V DC.
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