Table of Contents
Advertisement
Section 5
Circuit Description and Block Diagrams
This section describes only the differences between the LLC-8000A and LLC-8000. Therefore, read
Section "7. Circuit Description and Block Diagrams" of the LLC-8000 Service Manual (9-977-680-01)
together with this manual.
5-1. Signal Flow in LLC-8000A System
OPU
DISPCK-
DSIG
LLC-8000A
LLC-8000A
PGM
DISPDATA-
INCOM
LED ON
CPU-240 Board
MONITOR
LESPCLR-
AU-240 Board
+15 V
KEY DATA 0
PS-459 Board
GND
KEY DATA 1
IF-645A Board x 2
KEY DATA 2
KEY DATA 3
POWER
PSW2
PSW1
MIC
MONITOR SP
PHONE
METER
MTC1
DSIG
LINE IN
RS-232C
LINE OUT
ER-8020
+15 V
GND
MTC4
DSIG
LINE IN
LINE OUT
ER-8020
+15 V
GND
ROOM SP (L)
ROOM SP (R)
+15 V
GND
L
R
ROOM SP
LU-816A
IF-645A Board
PTU-8
+15 V
GND
PTU-8
+15 V
LU-816A
GND
IF-645A Board
LU-800B/LU-801B
ASW-58 Board
LLC-8000A
BOOTH TC No. 1
ER-8020
PC
BOOTH TC No. 32
DSIG
PGM
INCOM
ER-8020
MONITOR
+15 V
GND
BOOTH TC No. 33
DSIG
PGM
INCOM
ER-8020
MONITOR
+15 V
GND
BOOTH TC No. 49
DSIG
PGM
INCOM
ER-8020
MONITOR
+15 V
GND
BOOTH TC No. 64
DSIG
PGM
INCOM
ER-8020
MONITOR
+15 V
GND
5-2. Circuit Description
Refer to Section "5-1. Signal Flow" in the LLC-8000A System and Section "5-3. Block Diagrams".
1. Digital Control System
In the LLC-8000A Learning Laboratory System, data communications between the master tape record-
er model ER-8020 and the booth (student) tape recorders ER-8020, are established by RS-232C at the
signal speed of 2400 baud. For establishing communications, the serial input/output controller (SIO) is
installed in the CPU-240 circuit board of the control unit with four channels available for communica-
tions. The first channel is used for the master tape recorder, MTC1, and the booth tape recorders, Booth
TC, No. 1 to 16. Similarly, the second is for MTC2 and Booth TC, No. 17 to 32, the third is for MTC3
and Booth TC, No. 33 to 48, and the fourth is for MTC4 and Booth TC, No. 49 to 64. The four channels
as a whole establish communication routes for data and remote control commands among the control
console, the master tape recorders, and the booth tape recorders that form the system.
Data communication between the control unit of the LLC-8000A and the OPU is established by serial
IO signals. The control unit sends 32 bits of display data (DISPDATA-), in four segments of 8 bits and
low-active, to the OPU on the synchronous clock signal (DISPCK-) of 1.2288 MHz, and illuminates the
7-segment LEDs on the operation unit.
Key-input signals from the OPU, on the other hand, produce dynamic scan signals together with DIS-
PCK- and DISPCLR- signals, and are sent to the CPU-240 circuit board of the control unit as the key data
signals (KEYDATA0 to KEYDATA3). The other digital signals control the gate of the audio circuitry.
The "random pair" and the "group conference" formations are enabled by installing the optional
board ASW-58 board into the control unit that is controlled from a personal computer by GUI.
Communication between the personal computer and the CPU in the CPU-240 board is performed by
RS-232C at 9600 baud, and that between the CPU (IC60) on the CPU-240 board and the CPU (IC80)
on the ASW-58 board is performed also by RS-232C at 9600 baud. These communications control
the audio gates of the cross-point switches on the ASW-58 board.
2. Audio Signal System
Audio signals between the control console LLC-8000A and the booth tape recorders ER-8020 run
through the three routes: the program (PGM), the intercom (INCOM), and the monitor (MONITOR)
lines with the signal level of _10 dB.
The PGM line sounds reproduced signals from MTC1 to MTC4 to the booth TCs for each program.
INCOM sends microphone signals from the control console unit to the booth TC ER-8020, with the
ALL CALL or INCOM key pressed on the operation unit.
MONITOR sends audio signals of the booth TC ER-8020 to the control console as monitor signals,
with the MONITOR key pressed.
The optional board ASW-58 board is inserted between the booth TC ER-8020 and the MONITOR line of
the console LLC-8000A so that the MONITOR signals of the pre-set group of the booth TCs are mixed
by the ASW-58 board and then distributed to the MONITOR lines of the same group of the console side.
These connections enable establishment of the "random pair" and the "group conference "formations.
3. Power Supply System
The power supply unit, PTU-8, supplies +15 V DC to the control console, which is in turn converted
into ± 12 V, ± 6 V, +5 V, and A+5 V DC on the control console side.
The ER-8020s of the booth tape recorders and the master tape recorder are recognized as PSW2 signals
by the CPU-240 board input port when the POWER key of the OPU is pressed on. The PSW2 signal
than activates the +12 V relays on the IF-645A board that supplies the +15 V power.
The optional board ASW-58 board receives +15 V DC power from the power supply unit PTU-8 via
the IF-645A board. The ASW-58 board has power regulators that generate voltages of ± 5 V and +9 V.
5-1
5-1
Advertisement
Table of Contents
