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CHAPTER 4: Operation
Table 4-1. Fiber Optic Modem’s Front-Panel Controls and Indicators
Item No. Name
Type
Function
1
PWR
Green LED
On when the Power is on.
2
RTS
Yellow LED
On when the terminal activates
Request to Send.
NOTE:
The CARRIER jumper should be set to
ON; if set to CNTRL, the RTS signal
should be high.
3
TD
Yellow LED
On when steady SPACE is being
transmitted. Flickers when data is
being transmitted.
4
RD
Yellow LED
On when steady SPACE is being
received. Flickers when data is being
received.
5
DCD
Yellow LED
On when a valid receive signal is
present.
6
TEST
Red LED
On when the Fiber Optic Modem is in a
loopback mode or when the PATT
switch is pressed.
7
ERR
Red LED
On when the alarm buffer is not empty.
Flickers whenever an error is detected
in BER tests.
8
DIG
Pushbutton
The DIG (Digital) loopback switch
causes the local Fiber Optic Modem to
loop the received data back to its
transmitter (see
Figure 5-3
).
