Clear-Com TEL-14 - Manual (Page 9)

T E L - 1 4 T W O - C H A N N E L T E L E P H O N E I N T E R F A C E 1 - 3
"Ring/Off-Hook" LED
The "ring/off-hook" LED flashes red when the telephone line receives a ring
signal. The LED is green while the line is answered and in use. The LED flickers
yellow during the automatic hybrid nulling process. The LED is off when the
line is on-hook and not ringing.
"Hook" Button
The "hook" button allows a local operator to manually toggle the TEL-14 line
between "on-hook" (telephone line not in use) and "off-hook" (line "seized" --
that is, in use) status. If a line is seized at the interface by the "hook" button, that
line cannot be released from an intercom station, even if the “matrix control”
option switch is set. The line can be released only by either pushing the button
again, or by auto-disconnect (if the auto-disconnect option switches are set).
"Send Level" LED
The bi-color "send level" LED lights green when the audio signal being sent to
the telephone line is at a typical acceptable level. The LED lights red when the
audio output signal level is too high. In normal operation, the LED should light
green during speech and only flicker red intermittently. The “send volume”
control adjusts the level indicated by this LED.
"Send Volume" Control
The "send volume" control sets the level of the signal that the TEL-14 sends to
the telephone line by changing the AGC limiting level. It is only active when the
"auto gain" button is set to “adjustable.” The "send volume" control has a range
of 12 dB. Adjust ± the "send" control so that the "send level" LED always lights
green with no more than occasional red flashes.
"Receive Volume" Control
The "receive volume" control sets the level of the signal that the TEL-14 receives
from the telephone line by changing the AGC limiting level. It is only active
when the "auto gain" button is set to “adjustable.” The "receive volume" control
has a range of 12 dB. While setting the receive volume, listen to the output from
the telephone line in normal use. Adjust the “receive” control until the telephone
receive level is comparable to the volume level of other intercom listen paths.
"Auto Gain" Button
With the "auto gain" button set to fixed, the TEL-14 adjusts the audio gain to
limit the send and receive telephone line signals to normal levels. In the fixed
mode, the "send volume" and "receive volume" controls are disabled, but are in
effect set to their center positions. When the "auto gain" button is set to
“adjustable,” the TEL-14 adjusts the audio gain to limit the send and receive
telephone line signals to levels defined by the "send volume" and "receive
volume" controls. The TEL-14 remembers the setting of the "auto gain" button
when power is turned off.