Telos Zephyr Xstream User Manual page 53

When the V.35/X.21 interface is present (and selected) the Sync LED will be illuminated only if a
valid external clock signal at the correct frequency for the Bit Rate setting (in the CODEC menu)
is present on one of the two V.35/X.21 ports.
When the Ethernet interface is selected, the Sync LED will blink while the Xstream's clock works
to sync with the Xstream on the other side of the connection. Due to network conditions, it is
common for this light to be solidly on, and then start blinking again as the clock readjusts.
Lock 1 & 2 LEDs
The green Lock 1 and Lock 2 LEDs represent the codec decoder status. When a dual channel
receive mode is used (i.e. L3 Dual‐mono or G.722) the Lock 1 LED represents that the decoder is
locked (or "framed") to the incoming coded audio on "Line 1" while the Lock 2 LED represents a
decoder lock on an incoming audio stream on "Line 2".
In the case of a receive mode requiring both B channels (most stereo mode as well as mono 128)
both lock LEDs will illuminate only once a compatible pair of bit‐streams are present on both
"Lines".
Send Bargraph
The Send bargraph LEDs represent the level of audio into the coder section. This level is
affected by several factors: The output level of the device connected to the Zephyr Xstream; the
setting of the Ch "x" Gain option in the AUDIO menus; the mixer knob setting.
As with most digital equipment, these meters are calibrated in dBfs (decibels below full scale).
In other words, the top LED represents the clip point and the numbers are calibrated in dB
below full scale. Therefore, it is important that your levels be set to where the top LED is never
lit.
There is a transition of LED color at ‐10 dBfs. Since the meters are peak indicating, it will
generally be safe to run things into the red, depending on the desired headroom and the
dynamics of the material. When setting levels with a sine wave (tone), a level near the red
green boundary should be used.
h
HOT TIP!
The individual level for the audio of each of the 4 mixer inputs (post fader) can be monitored
on the first AUDIO menu. This permits viewing the ratio of the 4 inputs in the mix shown on
the main SEND bargraphs.
Receive Bargraph
The Receive Bargraph LEDs represent the level of the audio being decoded from the far end.
The level is monitored in the digital domain at the output of the decoder. The calibration and
characteristics of the Receive meter match those of the Transmit meter.
USER'S MANUAL
Section 3: GUIDED TOUR of the HARDWARE 41