TXD
RXD
CTRL
IND
STAT
CLK
PWR
Figure 9. Front of Model 2121, showing LED Indicators
TXD- Trasmit data LED (green) blinks to indicate data transi- tions and remains OFF when no data is transmitted (idle).
RXD- Received data LED (green) blinks to indicate data tran- sitions and remains OFF when no data is received (idle).
CTRL- Control LED (yellow)- turns ON at power up to indi- cate to the DCE that the 2121 is active.
IND- Indication LED (yellow) - turns ON when the 2121 is ready to receive data from the DCE.
STAT- Status LED (yellow) - Turns ON to indicate that a carri- er detect signal is received from the DCE.
CLK- Clock Signal LED (yellow) - blinks to indicate that the transmit clock from the DCE is active. The CLK LED will remain OFF to indicate the absence of the transmit clock.
PWR- LED (green) turns ON as soon as power is applied to the 2121/2135C.
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Figure 10. Front of Model 2135C, showing LED Indicators
TXD- Trasmit data LED (green) blinks to indicate data transi- tions and remains OFF when no data is transmitted (idle).
RXD- Received data LED (green) blinks to indicate data tran- sitions and remains OFF when no data is received (idle).
DTR- Data Terminal Ready LED (yellow)- turns ON at power up to indicate to the DCE that the 2135C is active.
CTS- Clear to Send LED (yellow) - turns ON when the 2135C is ready to receive data from the DCE.
DCD- Data Carrier Detect LED (yellow) - Turns ON to indi- cate that a carrier detect signal is received from the DCE.
CLK- Clock Signal LED (yellow) - blinks to indicate that the transmit clock from the DCE is active. The CLK LED will remain OFF to indicate the absence of the transmit clock.
PWR- LED (green) turns ON as soon as power is applied to the 2135C.
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