Installing and putting a SINAUT modem into operation
6.6 Analog dial-up modem MD3
SINAUT ST7 Station control system - System Manual
270
System Manual, 05/2007, C79000-G8976-C178-06
Table 6-24 Meaning of the LEDs on the front of the MD3 for dedicated line operation
LED no.
Labeling
Description
1
TXD
Transmit data
The LED flashes in rhythm with the data flow sent to the modem by the
terminal device (TIM) over the RS-232 or RS-485 interface.
2
RXD
Receive data
The LED flashes in rhythm with the data flow sent by the modem to the
terminal device (TIM) over the RS-232 or RS-485 interface.
3
DTR
Data terminal ready
This LED indicates the signal state of the DTR line of the data terminal
equipment (TIM). Due to the default setting of the MD3, the signal state
of the DTR line in the dedicated line mode has no effect on the modem.
4
RTS / ONL
Modem online (ONL)
The modem attempts to establish a connection to the partner modem
after power ON; in other words, the two modems attempt to
synchronize themselves. As soon as they are synchronized, the ONL
LED remains lit but the DCD LED goes off.
If there is no synchronization within 60 seconds, the ONL LED goes off
briefly and then lights up again to indicate that the modem is attempting
to synchronize once again.
5
CTS / RI
-
6
DCD
The LED has a dual function:
1. Operating status
This signals the operating status of the modem. The LED lights up after
the power is turned on if the operating voltage is correct. If the modem
is not operational, the LED remains off.
2. Connection established
The LED goes off as soon as the two modems involved in connection
establishment are synchronized (see also ONL). The LED lights up
when the connection was aborted due to a disruption.
The RTS, CTS and RI signal names are irrelevant for the MD3.
Front view of the MD3 with removed front panels
The following figure once again shows the front view of the MD3 modem, here, however, the
front panels have been removed to show the connectors located behind them.