Data Interfaces
SDM-2020 Satellite Demodulator
A–38
Rev.3
A.5.5
Monitor and Control Functions
A.5.5.1 System
Implementation
Refer to Table A-21 for signal definition.
Table A-21. Signal Definition
Signal
Definition
TA (Data Terminal Equipment Available)
LA (Loopback Circuit A)
LB (Loopback Circuit A)
These signals are inputs from the HSSI interface. The state of these inputs is
read by the M&C from the ECL/HSSI interface status register.
CA (Data Communication Equipment Available)
LC (Loopback Circuit C)
TM (Test Mode)
These signals are outputs from the HSSI interface. The state of these outputs
is controlled by the M&C writing the ECL/HSSI interface control register.
TA
This signal indicates the DTE is available for data transfers. When the DTE
is not available the RF output will be turned Off and the DTE status menu
shall reflect DTE unavailable.
LA and LB loopback input control signals
These signals are available to the M&C, but no functional support is
required.
Upon Modem power-up the CA output is set UNAVAILABLE until all modem
initialization has been completed and no faults are detected. After completion of
initialization the CA line is set AVAILABLE. Any detectable faults that cause the
modem to be place in an non-operational mode shall set CA UNAVAILABLE.
TM output shall be set ACTIVE if the ECL/HSSI interface is commanded into Loopback
mode. TM shall be INACTIVE for all other modes.
LC output is not supported, and is set inactive for all modes.
A.5.5.2 Faults
Refer to Table A-22 for ECL/HSSI fault indicators to the HSSI connector (Reserved
DCE pins) from the modem interface.
Table A-22. Fault Signal Definitions
Signal
Definition
Carrier Detect (CD)
Indicates Demodulator carrier tracking loop locked. Status output. TTL output. Active
High (programmable).
Modulator Fault (DF)
Open collector TTL signal indicating Demodulator fault. Active High. An external
pull-up resistor is required.
Modulator Fault (MF)
Open collector TTL signal indicating Modulator fault. Active High. An external pull-
up resistor is required.
Summary of Contents for SDM-2020
Page 32: ...SDM 2020 Satellite Demodulator Introduction Rev 3 1 17 This page is intentionally left blank...
Page 35: ...SDM 2020 Satellite Demodulator Installation Rev 3 2 3 Figure 2 1 Typical Rack Installation...
Page 57: ...SDM 2020 Satellite Demodulator Operation Rev 3 3 13 This page is intentionally left blank...
Page 65: ...SDM 2020 Satellite Demodulator Operation Rev 3 3 21 This page is intentionally left blank...
Page 72: ...Operation SDM 2020 Satellite Demodulator 3 28 Rev 3 This page is intentionally left blank...
Page 75: ...SDM 2020 Satellite Demodulator Operation Rev 3 3 31 This page is intentionally left blank...
Page 92: ...Operation SDM 2020 Satellite Demodulator 3 48 Rev 3 This page is intentionally left blank...
Page 209: ...Fast Option SDM 2020 Satellite Demodulator C 6 Rev 3 This page is intentionally left blank...
Page 212: ...SDM 2020 Satellite Demodulator Glossary Rev 2 g 3 W Watt...
Page 213: ...Glossary SDM 2020 Satellite Demodulator g 4 Rev 3 This page is intentionally left blank...