"Ring/Off-Hook" LED
The "ring/off-hook" LED flashes red when the telephone line
receives a ring signal.TheLEDisgreenwhilethelineisanswered
andinuse.TheLEDflickers 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 tomanually toggle the
TEL-14 line between "on-hook" (telephone line not in use) and "off-
hook" (line "seized" -- thatis,inuse)status. If alineisseizedatthe
interfacebythe"hook"button,that
line
cannot
be
r
e
leased
from
an
in
tercom
station,
ev
en
if
the
“
m
atrix
contr
o
l
”
option switch is set. The
line can be released only by either pushing the button again, orby
auto-disconnect (if the auto-disconnect option switches are set).
"Send Level" LED
Thebi-color"sendlevel"LEDlightsgreen whentheaudiosignal
beingsentto thetelephonelineisatatypicalacceptablelevel.The
LEDlightsredwhenthe audio output signal level is too high. In
normal operation, the LED should light
gr
een
du
ring
speech
and
only
flicker
r
e
d
intermittently.
The
“
s
end
v
olume
”
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
"autogain"buttonissetto“adjustable.” The"send
volume"controlhasarange
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
whenthe"autogain"buttonissetto“adjustable.”
The"receivevolume"control
hasa range of 12 dB.Whilesettingthe
receivevolume,listentotheoutputfrom
the
teleph
one
line
in
normal
use.
A
d
just
the
“
r
eceive
”
con
t
r
o
l
until
t
h
e
tel
e
phone
receive level is
comparable to the volume level of other intercom listenpaths.
"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
“
a
djusta
ble,”
the
TEL-14
adjusts
the
audio
gai
n
t
o
l
i
mit
the
send
an
d
r
eceive
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.
