Telos Zephyr Xstream - Manual (Page 219)

USER’S MANUAL
Section 11: THE WORKS – Detailed Menu Reference 207
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COMPTIBILITY TIP!
The Zephyr Xstream cannot receive two stereo feeds from the far end (after all, where would
the audio be output?).
When connected to two different sites simultaneously, you can receive an audio feed back
from each using G.722 or L3 Dual/Mono.
AAC Stereo
AAC J‐Stereo
These work similarly to the equivalent Layer‐3 modes (see above). Two
connections are required. These modes are important since they offer the best
quality ever over a single ISDN BRI circuit.
Offers 15 kHz audio frequency response, when the sample rate is set to 32 kHz
and 20 kHz response when the sample rate is set to 48 kHz.
AAC Mono 128
This uses both B channels transmit a single audio channel using the audio from
input A.
Offers 15 kHz audio frequency response when the sample rate is set to 32 kHz
and 20 kHz response when the sample rate is set to 48 kHz.
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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 AAC and AAC-LD, the Zephyr Xstream uses the Telos Zephyr IMUX protocol.
AAC Mono 64
This encodes a single mono bit stream using the A audio input. This bit stream
is fed to both ISDN B channels so it can be to feed identical mono to two sites.
Offers 15 kHz audio frequency response when the sample rate is set to 32 kHz
and 20 kHz response when the sample rate is set to 48 kHz.
G.722 (Dual/Mono)
Compatible with many other brands of codecs. We use the SRT (Statistical
Recovery Timing) method, which is the most common encountered by far.