Comtech EF Data SDM-650B - Manual (Page 290)

Asynchronous Overhead Channel Unit SDM-650B Satellite Modem
F–32 Rev. 5
F.5.2.3.4 Transmit Faults (TX_INTF)
The faults listed below are only displayed when the ASYNC overhead channel unit is
installed.
Refer to Section 6.2 for option explanations.
TX_PLL Interface transmit clock phase locked loop fault.
Clk_Act Clock activity fault.
Activity detector alarm of the selected interface clock. The interface will fall
back to the internal clock when this fault is active.
F.5.2.3.5 Receive Faults (RX_INTF)
The faults listed below are only displayed when the ASYNC overhead channel unit is
installed.
Refer to Section 6.2 for option explanations.
BUF_UNFL Buffer underflow fault.
Typically indicates that a buffer underflow has occurred.
BUF_OVFL Buffer overflow fault.
Typically indicates that a buffer overflow has occurred.
RX_PLL Interface receive clock phase locked loop fault.
Buff_Clk Buffer clock activity fault.
Activity detector alarm of the selected interface receive clock.
MUX_lock MUX lock fault.
Typically indicates that the MUX is not locked.