Comtech EF Data SDM-650B - Manual (Page 283)

SDM-650B Satellite Modem Asynchronous Overhead Channel Unit
Rev. 5 F–25
BERT_set This function is used to set the BER threshold. If the BER threshold set
is exceeded, a receive fault will be indicated by the modem status
indicators. BER threshold may be set from 1E-3 to 1E-8, or may be
disabled by specifying None.
On entry, the current setting of the BER threshold is displayed. Use [
↑ ]
and [ ↓ ] to select the desired setting. Press [ENTER] to execute the
change.
F.5.2.1.3 Configuration Interface
Refer to Table F-6.
TX_Clock Programs the modem for internal or external transmitter clock.
On entry, the current status of the transmit clock is displayed with the
flashing cursor on the first character. Use the arrow keys to select
internal or external transmit clock. Press [ENTER] to execute the
change.
Buf_clk Programs the interface plesiochronous buffer output clock.
External sets this clock source to the external reference clock. When
External is selected and there is no clock present at the rear of the
modem, the clock will fall back to the satellite clock.
Satellite sets the output buffer clock to the satellite clock. This is also
the fallback clock. If satellite is selected, the Doppler shift caused by the
satellite will not be removed.
Internal sets the buffer clock to operate from the modem internal clock.
When EXT_REF clock is selected and there is no clock present, a fault
will occur. The output buffer clock will not fall back to satellite clock.
On entry, the current output buffer clock is displayed with the flashing
cursor on the first character. Use the arrow keys to select the desired
clock source. Press [ENTER] to execute the change.
RX_clock Programs the modem for inverted or normal receiver clock.
On entry, the current status of the receive clock is displayed with the
flashing cursor on the first character. Use the arrow keys to select
inverted or normal receive clock. Press [ENTER] to execute the change.
EXT_REF Programs the data rate of the external reference clock.
Typically, this clock source is programmed to 1.544, 5, or 10 MHz.
On entry, the current setting for the external reference is displayed with
the flashing cursor on the first character. Use [
← ] and [ → ] to move the
flashing cursor. Use [ ↑ ] and [ ↓ ] to increment or decrement the digit at
the flashing cursor. Press [ENTER] to execute the change.