Telos Zephyr Xstream - Manual (Page 89)

USER’S MANUAL
Section 4: BASIC OPERATION & INSTALLATION 77
4.3 Codec Settings: Transmit, Receive, Bit Rate, & Sample Rate
When calling another ISDN codec (e.g. mode = Zephyr), these settings must be set correctly to
achieve an end‐to‐end bi‐directional audio connection. Since this is just an introduction, we will
just briefly tell you what each is. For more information, see Section 11 (detailed Menu
Reference). Section 6 (Audio Coding Reference) covers the different transmission modes in
detail, including the advantages and disadvantages of each.
NOTE: When placing a call to a telephone (mode = Phone), or to a Zephyr Xport that is on a POTS
line (mode = Xport) this settings can be ignored.
Transmit
This determines the format of the audio locally coded for transmission. In order for the far end
to receive this audio, the far end codec must:
1) Support this transmission mode; and
2) Must have its "Receive" (or "decoder") mode set appropriately to receive the
mode being sent.
3) The bit rate and sample rate settings must be matched between the two ends.
c
COMPATIBILITY TIP!
The AAC and AAC-LD standards are new, and are not supported by older codecs. When
communicating with older equipment, you must make some other choice.
The G.722 transmit mode is the most widely supported standard. The majority of codecs
support this mode. Since it has the lowest delay, it is frequently used for return feeds and IFB.
Receive
This instructs your Zephyr Xstream to decode a particular mode being transmitted from the far‐
end codec.
The easiest option here is to set Receive to the “Auto” setting. This mode will attempt to
determine the mode being sent from the far end, and internally set the Receive mode to match.
All you'll need to do is be sure your Sample Rate (see below) is matched to the far end. The
mode selected will then be displayed on the default menu and the codec status screen so you
can note it for future reference.
As the auto mode takes several seconds to determine the correct mode, there are times you
may wish to use a specific setting for Receive. In this case, your Receive mode must be set to
decode the stream being sent from the far end.