11
CHAPTER 2: Introduction
2.2 Front-Panel Indicators and Buttons
The front panel of the RS-232 Synchronous Multipoint Line Driver has five status
indicators (LEDs) as follows:
TD
Will light when data is transmitted by the local attached RS-232 device
(pin 2 is active).
RD
Will toggle as data is received from the remote RS-232 device (pin 3 is
active).
RTS
Will light when RS-232 device raises RTS to request data transmission (pin
4 is active).
In Constant Carrier Mode the RTS LED will always be on, causing the
remote Line Driver’s CD light to always be on.
NOTE
Constant Carrier Mode pertains to full duplex or simplex operation only.
In Switched Mode the RTS LED will only be on if RTS is asserted, causing
the remote Line Driver’s CD LED to light.
CD
Indicates status of remote Line Driver’s RTS signal.
If the remote Line Driver is in Constant Carrier Mode, the local Line
Driver’s CD LED will always be on.
If the remote Line Driver is in Switched Mode, the local Line Driver’s CD
LED will light when the remote device asserts RTS.
PWR
Indicates the presence of power.
Three pushbuttons are located on the front panel used for various testing
operations as follows:
TST
End-To-End Continuity Test (button provides test pattern for all test
operations)
LLB
Line Loopback Test
DLB
Digital Loopback Test
See
Chapter 5
for instructions on performing each test.
