ABB REL 551-C1 2.3 Series Installation And Commissioning Manual page 54

48
Configuring the short range fibre optical
modem
There are also some indication for supervision of the communication channel that can
be seen when the cover around the fibre optic connectors is removed. These LED's are
found above DIP-switch. The function of the LED's are explained in table 3.
Table 3: Indications
LED Colour Explanation
RTS Yellow Request to send
CTS Yellow Clear to send
DSR Yellow Data communication correct
DCD Yellow Detection of carrier signal
TXD Yellow Transmitted data
RXD Yellow Received data
RA Red Remotely detected problem with link
MA Red Memory function for problem with link
LO Green Link operation correctly
LA Red Locally detected problem with link
Sync Green Used when synchronisation is selected
Chapter 8
Configuring the digital
communication modules