3. Using the Front Panel
3160-A2-GB24-10 March 2001
3-9
Table 3-4. Data Port LEDs
Name Color Meaning
DTR
Green Monitors the state of interchange circuit CD (CCITT 108/1, /2) –
Data Terminal Ready received from the synchronous data DTE.
ON:
DTR is being asserted by the synchronous data DTE.
OFF:
DTR is not being asserted.
TXD
Yellow Monitors activity on interchange circuit BA (CCITT 103) –
Transmitted Data. This is the data sent from the synchronous data
DTE to the data port on the DSU/CSU.
ON:
Ones are being received from the synchronous data DTE.
OFF:
Zeros are being received from the synchronous data DTE.
CYCLING:
Both ones and zeros are being received from the
synchronous data DTE.
RXD
Yellow Monitors activity on interchange circuit BB (CCITT 104) –
Received Data. This is data sent to the synchronous data DTE
from the data port on the DSU/CSU.
ON:
Ones are being sent to the synchronous data DTE.
OFF:
Zeros are being sent to the synchronous data DTE.
CYCLING:
Both ones and zeros are being sent to the
synchronous data DTE.
CTS
Yellow Monitors the state of interchange circuit CB (CCITT 106) –
Clear-to-Send sent to the synchronous data DTE.
ON:
CTS is being asserted by the DSU/CSU.
OFF:
CTS is not being asserted.
RTS
Yellow Monitors the state of interchange circuit CA (CCITT 105) –
Request-to-Send received from the synchronous data DTE.
ON:
RTS is being asserted by the synchronous data DTE.
OFF:
RTS is not being asserted.
