Telos Zephyr Xstream - Manual (Page 218)

USER’S MANUAL
Section 11: THE WORKS – Detailed Menu Reference 206
c
COMPATIBILITY TIP!
When two channels are required for transmission (i.e. for Stereo, J-Stereo, and Mono 128) an
"inverse multiplex" (IMUX) scheme must be used to break the standard MPEG data stream
into two streams for transmission.
In Layer-3, the Zephyr Xstream uses the FHG/Telos Zephyr IMUX protocol. Other Layer-3
codecs support this method, allowing for compatibility among different codec manufacturers.
The Telos IMUX used in AAC and AAC-LD is available on our website to encourage
compatibility with other manufacturers that may choose to support AAC in the future.
AAC‐LD Stereo
AAC‐LD Joint
These work similarly to the equivalent Layer‐3 modes (see above). Two
connections are required. These (and the other AAC‐LD modes) modes are
important since they offer significantly lower delay than any mode other than
G.722.
Offers 14 kHz audio frequency response.
AAC‐LD Mono 64
This encodes a single mono bit stream, normally using the audio from input A.
This bit stream is fed to both ISDN B channels so it can be to feed identical mono
to two sites.
Offers 14 kHz audio frequency response.
AAC‐LD Mono 128
This use both B channels transmit a single audio channel using the audio from
input A. Both B channels are used for the best quality and "coding headroom"
later in the transmission path.
Offers 16 kHz audio frequency response.
AAC J‐stereo 64
This mode, while it offering reduced audio bandwidth, allows stereo
transmission over a single B channel. The resulting coded bit stream is output
over both B channels (if dialed) allowing the identical stereo audio to be sent to
two sites simultaneously).
Offers 10 kHz audio frequency response when the Sample Rate is set to 48 kHz
and 7 kHz audio frequency response when the Sample Rate is set to 32 kHz.