Instruction manual

Page 32
UTY4422-001 Page 32 of 74
8. No video data < 5 seconds and have MPEG sync.
9. COMPEL required and no COMPEL within last 2 minutes.
10. Selected audio not available.
Otherwise, OFF.
3.3 RELAYS
This IRD supports 1 alarm relay and 2 solid state user relays. The user relays are controlled via
COMPEL™ and the modem/terminal interface.
Note that the alarm relay is de-energized when the IRD’s power is off and the relay outputs are
shorted together.
3.4 PROGRAM SELECTION
Programs may be selected by network control and (if allowed by the network) by local user. A
multiplexed MPEG transport stream may support some number of separate programs. Each
program has a single video and some number of associated audio data streams associated with it
in the main transport stream. The programs are designated with a number, but if none is supplied
by the selection command (e.g. the ‘*’ designation) the lowest in number order will be selected
by the IRD.
3.5 AUDIO HANDLING
The selected program (see Section 3.4) has a number of separate compressed-audio data streams
associated with it. These are assigned 3-letter mnemonic designations. Any of these may be
routed to either the Ch1 or Ch2 stereo outputs on the back of the IRD, but not both at the same
time. The selected stream is a stereo or dual-mono signal. It may be routed to the L and R
connections in a specific relationship to the original audio connections at the uplink MPEG
encoder unit:
* * * CAUTION * * *
E-mail messages should be read as soon as possible after receipt, because
each message will be over-written by the next one.