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CHAPTER 3: Operation
C
ANCEL
Pressing the Cancel key stops the current activity and returns to the previous
menu. Repeat until the desired menu level is reached. When a submenu item
is displayed, press Cancel to exit the current display and return to the previous
menu.
U
P AND
D
OWN
A
RROWS
Up and Down Arrows scroll through the submenu items available in the
current menu.
LED D
ESCRIPTIONS
The CSU/DSU MS DBU has seven LED indicators: RS, CS, TD, RD, CD, ALM,
and TST.
RS (Request to Send)
Reflects the status of the Request to Send pin of the
DTE interface.
CS (Clear to Send)
Reflects the status of the Clear to Send pin of the
DTE interface.
TD (Transmit Data)
This LED is active when data is transmitted from
the DTE.
RD (Receive Data)
This LED is active when data is received from the
network.
CD (Carrier Detect)
This LED is active when frame synchronization is
achieved and the CSU/DSU MS DBU is ready to
transfer data.
TST (Test Mode)
This LED is on whenever the unit is in test mode.
ALM (Alarm Indication) This LED activates whenever an alarm condition exists.
Alarm conditions include:
• Open loop on network
• No frame synchronization
• Unit in dial backup
• Problem on dial-backup line