Operating instructions

DMD50 Universal Satellite Modem Theory of Operation
TM118 – Rev. 1.1 3-7
Form-C Contacts:
The UIM provides three Form-C Relays under processor control that appear at J15.
Mod Fault: De-energized when any transmit side fault is detected.
Demod Fault: De-energized when any receive side fault is detected.
Common Fault: De-energized when any fault that is not explicitly a Tx or
Rx Fault such as an M&C or Power Supply Fault.
Open Collector Faults:
The UIM provides two Open Collector Faults that appear at Pins 18 & 21 on J19.
Mod Fault: Will sink up to 20 ma (maximum) until a transmit or
common fault is detected. Will not sink current if a fault
is detected.
Demod Fault: Will sink up to 20 ma (maximum) until a receive or
common fault is detected. Will not sink current if a fault
is detected.
The open collector faults are intended for use in redundancy switch applications in order to
provide quick status indications.
3.3 Async Port / ES-ES Communications
This port is dedicated for ES-ES Communications supported by either RS232 or RS485 signal
levels. The baud rate and protocol can be selected from the Front Panel. The port may be
configured for a number of communications protocols. Overhead data to/from the UIM is routed
to/from the framer/deframer. This port is also used by SCC Framing for the in-band data.
3.4 Internal Clock
The time and date is kept in order to ‘time-tag’ system events. User can change the Internal
Clock via the front panel, Web Browser or Terminal ports.