JVC MC-8100U, Service Manual, Page: 56 / 100

MC-8100U
2-19
2.4 Maintenance Mode
2.4.1 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 connect-
ing 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.
*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.
2.4.3 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
1
and
2
are available at
any time. The operation
3
is available only when this unit is
in the “direct maintenance” mode. Regardless of the cur-
rently selected maintenance mode (remote or direct), all the
peripheral components must be turned on before turning on
the power to this unit.
2.4.4 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.
2.4.5 Maintenance Program
To perform maintenance on this unit, the maintenance program
software must be installed on the PC connected.
• Connector: D-Sub 9-pin (male)
• Pin Layout
2.4.2 Electrical Specifications
• Signal Format
Modem
H O S T
Modem
P C
LIBRARY
H O S T
LIBRARY
H O S T
P C
LIBRARY
(a) Remote maintenance
(b) Direct maintenance
RS-232C
RS-232C
S C S I
S C S I
RS-232C
S C S I
●
Maintenance by
the same host
●
Maintenance using
exclusive PC
Public Tel line
1
DCD (IN)
6
DSR
2
RXD (IN)
7
RTS (OUT)
3
TXD (OUT)
8
CTS (IN)
4
DTR (OUT)
9
NC
5
S-GND
Signal Level RS232C
Communication System Asynchronous half-duplex
Transfer Rate 9600 bps
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
1 2 3 4
6 7 8 9
5
NOTES:
In the “direct maintenance” mode, the host computer must
not respond to an AT command.