NEC Mcu 5000a Multipoint Control Unit Equipment Manual

							NECA 340-414-500 Revision 2.0 Page 3 of 14
MCU 5000A Multipoint Control Unit INT-001
Figure 1:   Unit Layout of MCU 5000A
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TPWR
CABLE SPACE
01 23 45 6 7
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024 6810121416182022
24 2628 (U) 1U = 1.75 inches (44.45 mm)
(B)
1B = 0.6 in. (15.24 mm) 
						

							Page 4 o f 14   NECA 340 -41 4-5 00 Revisi on  2.0
INT-001   MCU 5000A Mult ipoint Con trol Unit
5.  LOOPBACK TEST 
						

							NECA 340-4 14- 50 0  Revisio n 2.0   Page  5  of  14
MCU  5000A Multipoint Control  U nit   INT-001
Figure 2 :   MCU Loopback Points
REL AY   IP AF   MTSC  
MTSC   MTSC   M
TSC
REL AY   MTSC  
MTSC   M
TSC   M
TSC
(a)  1.5M LIF Loopback Points 
						

							Page 6 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
Video Signal Loopback Test
5.07
The video signal Loopback test is performed through the use of the PN 
Pattern Generator/Checker function of the V SW/LSD IF unit.  The PN Pattern 
signal sent from the PN Pattern Generator returns from the loopback point set to 
make the local side Loopback and input to the PN Pattern Checker.  The PN 
Pattern Checker compares and judges the sent pattern with the input one.  When 
the line rate of 1.536 Mb/s is selected, it is necessary to set the MUX switch to 
OFF on the EC H.221 MUX unit.  For software, a video switch I/O (PC) task 
controls this test.
Audio Signal Loopback Test
5.08
The audio signal Loopback test is performed by the test tone generation 
mode function of the A CODEC unit.  After the setting of levels (0 dBm0, -12 
dBm0, -24 dBm0, -36 dBm0) and frequencies (500 Hz,800 Hz, 1000 Hz, 1600 
Hz) of the test tone, measurement is taken for the levels of continuous output and 
loopback  tone.  Moreover, when the level measurement is selected as the 
operation, the measured level is displayed on the console screen.  For software, an 
audio controls I/O (VC) task controls this test.
LSD Loopback Test
5.09
The LSD (Low Speed Data) Loopback test is performed at the HSCX of 
the V SW/LSD IF unit. The LSD (four frames  of  00H to 7FH data) sent from the 
HSCX returns through the loopback point set to make the local side Loopback and 
is input to the HSCX.  It compares and judges the sent  LSD with the input one.  
For software, a LAP-B driver (LD) task controls this test.
Console Loopback Test
5.10
The console Loopback test is performed at the serial controller of the PG/
SIO unit.  The loop setting is done automatically in the console Loopback test.    
Two kinds of loop points can be set.  One makes the loop in the serial controller 
and the other makes the loop outside the RS-232C connector and allows the 
control signal test. When the outside loop is selected, it is necessary to set the loop 
connector.  The transmitted data is set to be  four  frames of 00H to 7FH data.  For 
software, a console drive 1, 2 (CD 1, 2) tasks control this test. 
						

							NECA 340-414-500 Revision 2.0 Page 7 of 14
MCU 5000A Multipoint Control Unit INT-001
Diagnosis
5.11
The M CONT unit conducts the diagnosis of the hardware during the 
initial processing after power-up, and the result is indicated by the LED.   When  a 
failure has occurred during the operation, the failure condition is also indicated by 
the LED.
• ST8:lights when the battery voltage of the memory card drops or the mem-
ory card is not mounted.  When the memory card is not mounted, reset and 
restart after mounting it.  If the LED still lights up after the restart, replace 
the battery of the memory card.
• ST7 to ST1:  steadily indicate.
5.12
In normal operation, some LEDs are blinking to give HEX indication of 
the number of the task under execution by the CPU.  However, when an 
abnormality has occurred, LEDs stop blinking indicating the number of the task 
where the abnormality has occurred.  The Table 2 shows abnormal indication of 
LED status (LEDs 1 to 6 and LED 7) on M CONT unit.
Table 2: Failure Indication
ITEM 
NO.LED INDICATION TYPE OF FAILURE SIGNIFICANCE ACTION TO BE TAKEN
1
RAM test errorRAM test error occurred during the 
initial processingReplace M CONT unit
2
ROM test errorROM test error occurred during the 
initial processingReplace M CONT unit
3
CPU H/W initialize 
errorInitializing error occurred in the 
peripheral circuit of CPUReplace M CONT unit
4 System parameter 
backup errorContents of system parameter was 
destroyed.Reset system parameter 
referring to “System Parameter 
Practice”. Replace battery of M 
CONT unit if failure occurs again.
5
Program load errorFailure in loading programs from the 
memory cardReplace memory card. Replace 
M CONT unit if failure reappears.
6
Abnormal loader 
operationAbnormality was detected in the 
program load processingReplace memory card.  Replace 
M CONT unit if failure reappears.
7 All the other 
indicationsProgram 
abnormalityAbnormality was detected in executing 
programs.  Task number is indicated.Replace memory card.  Replace 
M CONT unit if failure reappears.
Note:    : Lighted  : Unlighted 
						

							Page 8 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
6.  TROUBLESHOOTING
6.01
There are two methods for troubleshooting.  One sectionalizes the failure 
according to the failure conditions (output state  of  the  video  and  audio)  and  
the  other  does  it  in accordance  with  the  LED indication of each unit.  The 
following describes the procedure of sectionalizing failures of the MCU 5000A 
through the combined use of above two methods.
A. Sectionalization in 
accordance with 
Failure Conditions6.02
Check points are given in Table 3 in cases where failures of video and 
audio signals occur separately or simultaneously.  Carry out the failure 
sectionalization according to Ta b l e  4.
Table 3: Troubleshooting in Accordance with Failure Conditions
FA I L U R E  
CONDITIONPOINT OF FAILURE CHECK POINT REFERENCE NO.
Failure of both 
video and audioFailure of power 
system_ AC power supply
_ Power cord
_ DC output of PWR unitTCP-001
Failure of line_ Lines between 
conference
  roomsTCP-002
_ Lines between 
conference
  roomsTCP-002
Unit failure of MCU 
5000AM CONT unitTCP-005
1.5M LIF unitTCP-006
RS-422 LIF unitTCP-007
H0-INF LIF unitTCP-008
EC H221 MUX unitTCP-009
PG/SIO unitTCP-010
Failure of videoVideo signal
(V SW/LSD IF unit)TCP-014
TCP-022 (VDSW)
Failure of audio 
systemAudio signal (A CODEC 
unit / A SUM unit)TCP-015
Failure of video onlyUnit failure of MCU 
5000AM CONT unitTCP-005
Failure of videoEC H221 MUX unitTCP-008
V SW/LSD IF unitTCP-011
Failure of audio 
onlyUnit failure of MCU 
5000AM CONT unitTCP-005
Unit failure of MCU 
5000AA CODEC unitTCP-012
Unit failure of MCU 
5000AA SUM unitTCP-013 
						

							NECA 340-4 14- 50 0  Revisio n 2.0   Page  9  of  14
MCU  5000A Multipoint Control  U nit   INT-001
B. Sectionalization by  
						

							Page 10 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
Table 4: Troubleshooting by LED Indication of Each Unit (1 of 2)
UNIT LED ALARM FAILURE REFERENCE NO.
1.5M
LIF
unit/
H0-INF
LIF
unitRC1
RC2REC NOS of CHI (CH5) (input off)
 LOS (out of synch)
TCP-006/TCP-008 AIS AIS of CHI (CH5) (network side fault)
RAI RAI of CHI (CH5) (remote alarm)
Normal CHI (CH5) other than the above alarms or 
normal
RC3
RC4REC NOS of CH2 (CH6) (input off)
LOS (out of synch)
AIS AIS of CH2 (CH6) (network side fault)
RAI RAI of CH2 (CH6) (remote alarm)
Normal CH2 (CH6) other than the above alarms or 
normal
RC5
RC6REC NOS of CH3 (CH7) (input off)
LOS (out of synch)
AIS AIS of CH2 (CH7) (network side fault)
RAI RAI of CH3 (CH7) (remote alarm)
Normal CH3 (CH7) other than the above alarms or 
normal
RC7
RC8REC NOS of CH4 (CH8) (input off)
LOS (out of synch)
AIS AIS of CH4 (CH8) (network side fault)
RAI RAI of CH4 (CH8) (remote alarm)
Normal CH4 (CH8) other than the above alarms or 
normal
RS-422
LIF unitRC1
CH1Slip in port 1 of CH1
TCP-007 RC2 H221 in synch
RC3
CH2Slip in port 2 of CH2
RC4 H221 in synch
RC5
CH3Slip in port 3 of CH3
RC6 H221 in synch
RC7
CH4Slip in port 4 of CH4
RC8 H221 in sync 
						

							NECA 340-414-500 Revision 2.0 Page 11 of 14
MCU 5000A Multipoint Control Unit INT-001
 
Table 4: Troubleshooting by Led Indication of Each Unit (2 of 2)
UNIT LED ALARM FAILURE REFERENCE NO.
EC H.221
MUX
unitRE16 REC H221 out of synch
TCP-009 RC15 REM ALM H221 receives A bit (REALM)
RC10 FUN ERR Function test error of MUX
RC9 MEN ERR Memory test error
PG/SIO
unitRC1 CLOS Loss of line clock input
TCP-010 RC2 SLP 3Phase slip between line clock and 
10.752 MHz clock
RC3 SLP 2Phase slip between line clock and 
4.096 MHz clock
RC4 SLP1Phase slip between line clock and 
1.544 MHz clock
M CONT
unitRC18 ST8 Low battery voltage of memory card
Refer to GSD-009 RC13 ST7 ABEND or RAM/ROM error
RC12~7 ST6~1During normal operation: Task number 
indication
In case of ABEND: ABEND task number 
indication
RC6 MC Lights during memory card access
V SW/LSD
IF unitRRM ARM ARM of PN PatternTCP-011
A CODEC
unit--
-TCP-012
A SUM
unit--
-TCP-013 
						

							Page 12 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
7.  REPLACEMENT OF UNIT
7.01
When the replacement of unit is required as a result of troubleshooting, 
mount the unit correctly referring to the unit layout in Fig. 1.
7.02
Refer to TCP-017
 for the replacement of the unit.
8.  HANDLING OF MEMORY CARD
8.01
This section describes the handling of memory card mounted on the M 
CONT unit.  This memory card is of SRAM type and backed up by a lithium 
battery.
A. Replacement of 
Battery8.02
WARNING:  IN REPLACING THE BATTERY DUE TO CAUSES SUCH 
AS VOLTAGE DROP, MOUNT THE MEMORY   CARD   ON   THE   M CONT  
UNIT   AND   KEEP  THE  POWER  OF MCU EQUIPMENT ON (THUS POWER 
IS FED TO THE MEMORY CARD
).  THE CONTENTS OF MEMORY CARD 
DISAPPEAR IF THE BATTERY IS REMOVED FROM THE MEMORY CARD 
BEING PULLED OUT OF THE EQUIPMENT.
8.03
Periodical replacement of  the battery in accordance with the following.
8.04
Refer to TCP-018
 for the battery replacement procedure.  (For the 
mounting of memory card, refer to TCP-021
.)
B. Checking and 
Copying of 
Memory Card8.05
Checking the insertion condition of the memory card in use, detection of 
low battery voltage and write-protect and checking the kind of memory are  
conducted by executing the RMCS
 command.  Refer to TCP-016
 for execution 
procedure.
8.06
System parameters written on the memory card can be copied down on 
another memory card.  Refer to TCP-020
 for execution procedure.
C. Care in Handling 
Memory Card8.07
In handling memory card, following precautions should be observed.
• There is a write-protect switch at the front end of the card.  The switch is set 
at write-protect ON position. Do not change this setting.
• Do not give a strong shock to the card by dropping or bending by hand.
• Keep the memory card in the PVC case so  that the dust may not enter the 
connector part.
• Store it keeping off high temperature and humidity.
• Do not touch the connector part.
OPERATING CONDITION 24-HOUR DISCHARGE 8 HOUR/EACH TIME DISCHARGE
Replacement Interval 5 years One year