Studio Technologies IFB Plus 2001 - Manual (Page 22)

Issue 7, November 2001 Model 2 User Guide
Page 22 Studio Technologies, Inc.
up position, labeled MAN OH for manual
off hook, places the interface in the off-
hook state. If loop current is detected, the
interface will stay in the off-hook state and
the loop current LED will light. If loop
current is not detected, the interface will
return to the on-hook (idle) state after a
few seconds. Momentarily pressing the
switch to down position, labeled HANG
UP, disconnects the interface from the
telephone line. An apparent problem
occurs if the switch is used to place the
interface in the off-hook state and then
immediately used to hang up the inter-
face. A pause of approximately three
seconds is required before the manual
hang-up function becomes active after the
interface is manually taken off hook. This
is due to the charge time of a debounce
capacitor required in the auto answer
circuit. This capacitor is not associated
with interface 1 and the pause is not
required. In the standard audio mode,
the interface control switch is not active
because the standard audio mode places
the interface permanently in what is effec-
tively the off-hook condition.
A second switch controls the audio rout-
ing through interface 2. In the center
position, audio is received from the tele-
phone line. In the up position, labeled
SEND CH1, composite IFB channel 1
audio is sent out the interface. In the down
position, labeled SEND CH2, composite
IFB channel 2 audio is sent out the inter-
face. The overall send level is not adjust-
able. Just like the talent amplifier and line
outputs, the interrupt level is fixed, and the
program level is adjusted in reference to it.
The send level has been internally config-
ured to give the highest signal level pos-
sible, without overloading the telephone
company equipment.
On interface 2 a level trim pot is provided,
allowing the receive audio to be adjusted
over a ±8dB range. A quiet signal can be
boosted, and a “hot” signal can be attenu-
ated. The trim pot is accessible via a small
hole in the front panel, directly to the right
of the routing control switch. The trim pot
is active only in the receive mode.
Monitor Output
A level control and source select switch
is associated with the monitor section. The
level control adjusts the output level sent
to the external monitor speaker. IFB chan-
nel 1 is monitored when the source select
switch is in the up position. In the down
position, channel 2 is monitored. The mid-
dle position is labeled OFF and the moni-
tor amplifier is, as you might guess, off!
Power Indicator Light
A red LED indicator light located on the
right side of the front panel is lit any time
mains power is applied to the Model 2.
Since the Model 2 does not contain a
power switch, the power LED should be
lit at all times that power is applied to your
equipment racks.
It’s Time to Use the System!
Operation can commence after the Model
2 and related equipment have been in-
stalled and connected. The power LEDs
on the Model 2 and, if present, Model 32
and/or Model 33 Talent Amplifiers should
be lit. If one or more Model 22 Access
Stations are installed, their push button
switches should be dimly lit.
Ear pieces should be connected to the
talent amplifiers. Both the Model 32 and
Model 33 Talent Amplifiers utilize a ¼-inch
2-conductor phone jack for their audio
output. On the Model 32, either IFB chan-
nel can be selected as the audio source.