JVC MC-8200LU Service Manual page 22

2.10 Maintenance Mode
2.10.1 Outline
This unit is also equipped with an RS-232C port as an interface
for external equipment other than the SCSI interface which is
used for connection to the host computer. The RS-232C port is
used mainly for the following two purposes:
(a) Remote Maintenance:
It can be used for remote diagnostic operation by connecting
to the public telephone line via a modem.
(b) Direct Maintenance:
It can be used for diagnostic operation by direct connection
to a computer, etc.
In either way, while this unit is operated in the system the me-
chanical operation checking, which is one of the checking func-
tions of the self-diagnosis operation, is not available.
(a) Remote maintenance
RS-232C
Modem
Library
S C S I
HOST
(b) Direct maintenance
●Maintenance by
the same host
Library
RS-232C
HOST
S C S I
*Judgment whether remote or direct maintenance Checks
whether the modem is connected or not when the power is
turned ON, and judges the unit is in the "remote maintenance"
or "direct maintenance" mode.
· The modem control AT command (Z: Reset) is transmitted to
the RS-232C port. And if there is a response, the unit is oper-
ated as the "remote maintenance" mode, and if there is no
response, the unit is operated as the "direct maintenance"
mode.
NOTES:
In the "direct maintenance" mode, the host computer must
not respond to an AT command.
2.10.2 Electrical Specifications
• Signal Format
Signal Level RS232C
Communication System Asynchronous half-duplex
Transfer Rate
Character Start bit: 1
Data: 8 bits
Parity: None
Stop bit: 1
Codes used ASCII character code
Modem Control Command Compliant to Hayes AT command
Compatible Modem ITU-T V.32
Public Tel line
Modem
PC
●Maintenance using
exclusive PC
RS-232C PC
Library
S C S I
HOST
9600 bps
• Connector: D-Sub 9-pin (male)
• Pin Layout
1
DCD (IN)
2
RXD (IN)
3
TXD (OUT)
4
DTR (OUT)
5
S-GND
1 2
6 7
2.10.3 Maintenance Types and Conditions
1
Operating environment status
Outputs the environmental conditions including the type of
this unit (Model No.), status of connected drives, SCSI ID
No. setting and ROM version, etc.
2
Trouble contents check
Outputs the trouble information stored in this unit.
3
Self diagnostic function
Performs the preset specific operations and outputs the re-
sults as the status. Operations
3
time. The operation is available only when this unit is in
the maintenance mode. Regardless of the currently selected
maintenance mode (remote or direct), all the peripheral com-
ponents must be turned on before turning on the power to
this unit.
2.10.4 Activating the Maintenance Mode
To activate the maintenance mode with this unit...
1
Set the maintenance disc in the address 1 before turning the
power ON.
2
While pressing the MODE switch on the front panel, turn the
power switch to ON.
2.10.5 Maintenance Program
To perform maintenance on this unit, the maintenance program
software must be installed on the PC connected.
6
DSR
7
RTS (OUT)
8
CTS (IN)
9
NC
3 4 5
8 9
1 2
and are available at any
2-18