Wegener Communications UNITY 4600 - Manual (Page 17)

Unity 4600 User’s Manual
www.wegener.com 9 800032-01 Rev. F
1.4 Safety Summary
The U4600 is designed for safe use with few special precautions required of the user. The
following items are basic precautions to use when installing and working with your U4600:
Do not open the U4600 chassis cover.
This U4600 unit incorporates security labels over some of the screws. There are no user-
serviceable components within the U4600 unit. Tampering with these security labels or
opening the unit will void your warranty. If you have questions, contact Wegener's Cus-
tomer Service Department at the address or numbers listed under Customer Service.
1.5 Glossary of Terms and Abbreviations
ASI Transport Input Option
DVB-ASI Input One input per DVB ASI per EN50083-9 Annex B
Physical layer 270 Mbaud signaling on 75 Ω coax cable
Minimum byte gaps Down to 0-byte interbyte gaps
Transport data rate Limited to rates allowed by parent IRD
Table 1.2: Transport-In Options
Characteristic Specification
Table 1.3: Glossary of Terms
Term Definition
Ad avail, digital The opportunity for a local program splicer to insert local content in the MPEG PES streams in
substitution for “regular” network-distributed programming. The avail is bounded by “splice out” and
“splice in” points. "Splice points" are seamless insertion points (located for the splicer by DPI
messages) where the compressed stream may be broken and substituted without frame-by-frame
interruption of video.
Ad avail, analog The opportunity for local users to switch from the network-supplied programming to locally-
generated content (commercials). This is signaled by use of DTMF tones or closures of cue relays.
Alarm A condition or notification of a condition that prevents proper U4600 functioning.
Application
Software The main host software which sets up the unit hardware, runs the process of acquiring transport
stream sources, sets up and monitors the demux and decompression processes, monitors unit
operations, and interfaces with the network and local users.
ASI (or DVB-ASI) An “asynchronous” bit-serial physical interface for transport streams. Transmitting and receiving
functions are designed such that the time relationships between all packets and their timing
references are unchanged.
Audio Language
Descriptor Legacy 3-character MPEG descriptor applied to a program’s audio streams. It was originally
allocated to designate languages, but is now used for generic identification.